[pwdisswordfish4]

> We changed how our sessions work to get around it

In other words, you fixed the bugs in how your original implementation relied on bad assumptions that it shouldn't have tried to rely on to begin with.

The only real quibble here might be that duplicate requests cost you unnecessary transit.

[eloff]

Duplicate POST requests are a violation of the HTTP standard because they are not assumed to be idempotent. I hope you're just misunderstanding the problem.