Agreed, it's important to save example files that show potential bugs like this. Honestly I don't really advise consistent overwriting of files in general, actually. We have incremental save in there and it's quite useful. So many times I've seen people on here lamenting that they overwrote a TGD with a feature they ended up liking and wanting to use again later. Why overwrite? TGDs are small, hard drive space is cheap.
Anyway, what I would try next for troubleshooting would be to increase Displacement Tolerance in the Planet node.