Odd Cache Behavior

[Armeth.3145]

I have a job that runs every 5 minutes and pulls data from /v2/commerce/transactions/history/sells. The same stale data is returned every time for hours. If I hit the endpoint with postman once, I see the stale data. If I hit it a second time, I see the stale data. When I hit the endpoint the third time, it seems to invalidate cache and finally returns updated data. Does anyone have an idea of what might be happening or how I could work around this?