Random Blueprint Compile errors

Hey, just wanted to see if anyone knows why this is happening and how to avoid it. But what is happening is when I save my project and all files in it, everything is in good working order. And when I reopen it, I get errors saying the blueprint cannot compile, but when I go into the blueprint it either has false errors and compiles after a click or a reference node has been removed from a function. Any thoughts on this?

I had the same issue with BPs in projects from older engine versions and edited in newer versions. To solve it I only had to remove the contents of the Saved and Intermediate folders.

In order of BP dependencies -> Recompile -> Resave -> Reload Project

BP corruption was a big problem for a while, and it still happens occasionally.
Pretty scary! I test regularly by copying code to more recent editor versions.

Drag the files between open sessions & conversion is done in the background.
If the new file opens and everything looks good, you know you’re good to go.

You have to go forward though! Developing in 4.10 and migrating to 4.15 etc.
So far the engine has accommodated this despite all the changes underneath!