Checksum variance of compiled pof/sof images from one version of Quartus to another.

1. You'll probably need to contact altera (directly or via your FAE). Have you raised a ticket via mysupport?

2. No

3. If the design contains asynchronous elements, LCELLS to manually delay signals and other poor design practice (like no timing specs) it can quite easily cause differences from one compile to another, simply by a different placement. I have seen designs fail and pass based on changes like this (and even seen people ship designs with signal tap left in simply because it worked!).

make sure you get exactly the same version, as different services packs and windows/linux versions will produce different results.