CS0009 Metadata file Myextensions.Core3.dll could not be opened

I am periodically getting this error in LINQPad 6:

CS0009 Metadata file ...\AppData\Local\LINQPad\MyExtensions\3.1.0\MyExtensions.Core3.dll could not be opened -- PE image doesn't contain managed metadata.

This occurs when I start a new query or edit an old query.

Using Ctrl-Shift-F5 to unload seems to fix the issue, otherwise the editor doesn't seem to recognize the My Extensions methods.