Comment 2 for bug 212193

It's nothing to do with bzrtools. Bzrtools isn't even being loaded.

The problem appears to be that the remote branch is in a format earlier than dirstate-tags and its revision-history doesn't follow the lefthand history. Bazaar used to consider this okay, but newer formats use the lefthand history exclusively.

The local branch appears to be in dirstate-tags or a more recent format, so it follows the lefthand history, and the branches disagree about what history should look like.

Upgrading the remote branch to dirstate-tags or later should fix this problem.