SourceTree unexpectedly crashes when I stage a couple of files and then click on the Commit button on the toolbar

There is a number of repository bookmarks having been added and some of these repositories seem to be no longer available if I read the log file correctly (although not the one I am trying to commit to)

The attached error log contains all the technical details, although I had to obfuscate some file paths and URLs as they originally contained sensitive business information I am not authorized to reveal to a 3rd party.

I should also add this is a second or third time SourceTree crashes under similar circumstances since updating to the latest version.