The complaints from Amazon customers are similar and popping up across the US. From western New York to central Missouri to rural Washington state, some Amazon Prime members are asking a version of the same question: What happened to Amazon Prime’s two-day shipping?

As Amazon brings next-day and same-day Prime delivery to more parts of the US, complaints from some Amazon customers about long Prime delivery times are still common in other regions. And one of those customers, a longtime former Amazon employee, recently conducted informal research that indicates Prime customers have to wait four or five business days for delivery across various parts of Amazon’s home state of Washington.

Amazon boosted Prime’s annual price to $139 earlier this year, and its signup page boasts, “Look for the Prime check mark as you shop. It means fast, free delivery!” But Prime members in some parts of the country have been surprised by slower delivery speeds than they were once used to. And it raises key questions: Are cracks appearing in the membership program at the core of Amazon’s e-commerce domination? Or is Amazon intentionally slowing delivery speeds for some Prime customers?

The inconsistency has been especially puzzling to a former Amazon employee named Peter Freese. Freese worked in Amazon corporate roles for more than a decade, including three years leading data analysis work in the company’s transportation and fulfillment divisions. He knows better than most how things work behind the scenes after a customer places an order.

But in July, he was surprised to find that Prime’s free two-day shipping, the hallmark of Amazon’s membership program, appeared to no longer be available on any merchandise whatsoever in his hometown of Omak, Washington, about 200 miles northeast of Seattle. Instead, Prime two-day shipping had been replaced by a delivery speed reminiscent of the 1990s: five business days.

He surmised that he was either witnessing the results of a technical bug that was potentially costing the company sales, or a cost-cutting move that essentially meant Amazon was, in Freese’s words, “redefining the word Prime” for some customers — but with zero disclosure.

After reading similar complaints on social media and suspecting a potential broader issue, Freese ran an experiment in August to test Prime delivery promises in all 39 counties in Washington state. He found that in a third of the counties, 13 in total, Prime orders would take either four or five business days to arrive. (He chose a random residential address in the biggest city or town in each county.) These orders still carried a Prime badge on the checkout page, but had the simple branding of “FREE delivery” rather than any mention of “two-day” or “next-day” shipping. Freese’s experiment included five separate bestselling products, all sold and shipped by Amazon, including an Amazon Fire TV Stick, a pack of Amazon’s own brand of diapers, and a 64-ounce container of Tide detergent. While not exhaustive, Freese’s experiment appears to back up complaints from some customers about bizarrely slow delivery speeds.

Amazon spokesperson Lauren Samaha said the company has not identified any widespread issues with Prime delivery speeds and that Amazon is not slowing down deliveries to some members in an effort to cut costs. Instead, she said Prime delivery promises fluctuate based on many factors including transportation capacity in a given region and a customer’s location. She also denied the possibility that Amazon had stopped offering two-day Prime shipping to some parts of the US where it was previously available, despite some customers having that very complaint. Amazon’s website says that “nearly all addresses in the contiguous US” qualify for two-day Prime shipping.

In his Prime shipping experiment focused on Washington, Freese was especially surprised that one of the counties with slow delivery speeds was Spokane, because Amazon has opened two new fulfillment centers there since 2020. So to dig a little further into potential issues there, Freese tested an extra three addresses in different parts of Spokane County, and five extra Prime-eligible products for a total of 10. He found that only one of the four delivery addresses in Spokane had faster delivery speeds than five business days. And for that faster address, four of the 10 products still didn’t qualify for two-day Prime shipping.

“If this is all a bug, then it’s extra gnarly and will be confusing to unravel,” Freese told Recode, referencing the disparities between Spokane addresses. “If it isn’t a bug, are they actually targeting certain neighborhoods for exclusion?”

On social media, Amazon customer service reps often counter these complaints or questions by pointing out that Prime’s two-day shipping promise begins at the point that an item is shipped from a warehouse — not at the moment a customer places the order. They also often make clear that the two-day phrasing really means two business days, not two calendar days. That is and has long been the fine print of Prime membership. But any longtime Prime member knows that, for many years, Prime packages usually showed up two days after a customer placed an order. That’s what Prime members have come to expect from Amazon. And that expectation has fueled the explosive growth of Amazon Prime, which today has more than 200 million paying members across the globe.

Freese’s analysis goes beyond those semantics, though: What he’s found is that some customers who once had Prime two-day shipping no longer do, even on commonly purchased items. Yet they’re still paying the full Prime membership fees like everyone else.

Of course, Prime delivery speeds cannot be discussed in full without acknowledging the million-person Amazon workforce in the US that works under fine-tuned surveillance and exacting quotas to pick, pack, and deliver customer orders at a pace that has made Prime’s typically fast delivery speeds possible in the first place. These conditions have at times led to above-average injury rates and sky-high employee turnover, which have threatened to exhaust the pool of people willing to work at Amazon warehouses in some geographies, according to Amazon’s own research.

There’s a reason why Amazon warehouse workers for the first time in the US voted to unionize earlier this year, albeit at a single Amazon facility. Efforts to vote to unionize are already underway at other Amazon facilities across the US.

Amazon has also said this year that it needed to pull back on expansion plans as consumer demand weakened two years into the pandemic, and as the company recognized it had overestimated how much warehouse space and staffing it would need. The logistics consulting firm MWPVL International Inc., which tracks Amazon’s warehouse network, “estimates the company has either shuttered or killed plans to open 42 facilities totaling almost 25 million square feet of usable space [and] delayed opening an additional 21 locations, totaling nearly 28 million square feet,” according to Bloomberg.

Now, the inconsistency of Prime delivery expectations in some locales is another reminder that cracks may be showing in the well-oiled Amazon retail machine that for so many years seemed to run with little obstruction.