How do I deal with these issues that arise seemingly at random?

I found an answer for the grass that I couldn’t find last time.
“RemoveLandscapeXYOffsets” in the console. You can do “grass.flushcache” after, which I didn’t seem to need but I’ll put it here for anyone who may find this.

For the water I just made a new material with the exact same setup as far as I can tell and it works.

I’ll leave this open in case someone knows a way to prevent these things from happening again and wasting time I guess.