Comment 35 for bug 1865515

Further analysis today suggests the issue is that shim never uninstalls the old shim protocols, and then things get weird. Patching shim to call to the parent shim to uninstall itself, rather than falsely attempting to uninstall it ourselves, makes it work, but it's just a hack so far.

We can patch this properly I suppose by introducing a new shim protocol that can be used to uninstall shims, but this is obviously a problem, as you'll need updated shims on both the maas server and the client.

So, while I think we understand the issue better, I'm afraid this looks to be a long term issue that needs fixes in all other distros you want to load as well, and agreement with upstream on how to solve.