I have another case with "checksum mismatch" error while module fetching. In my case we use golang module's git repository with git-lfs plug-in. Some of developer had git-lfs some didn't have and that cause race condition in go.sum.

We temporally resolve problem by install git-lfs on all developer's computers, but later we turned off git-lfs support in repository with private modules.

Our temporally decision was :

sudo apt install git-lfs