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.