Sketchup creating weird geometry while modifying solids

This has happened to me a lot during the last few days. When I´m trying to modify something or even just moving it, it completly deforms. I tried undoing it but it doesnt work. Does someone know how to fix it?

This happens to me when 1) a Check Validity function has been performed (such as when doing a Save), found problems in the model, and I gave permission to “fix” them, and then 2) I Undo the Check Validity result. The Undo often causes such long triangles to be generated. Undo a few more times (5 or 10 more times are required occasionally) and the bogus long triangles are removed. But that means manually re-doing work that you undid. So I have learned basically to never Undo a Check Validity operation.

How far is your model form the origin?

this can also happen if you have raw geometry assigned to a tag/layer that would at some point be hidden and revealed