Jeff,
there were indeed some improvements, in late 2018, on the undo/redo framework.
So chances are good, that a newer release will solve your issues.
You can use the latest nightly build for Windows here:
https://sourceforge.net/projects/librecad/files/Windows/NightlyBuilds/master/LibreCAD-Installer-2.2.0-rc1-142-ge38b7088.exe/downloadThis version should be as stable or even more stable than your current version.
Armin
investing less than half an hour into Search function can save hours or days of waiting for a solution