Calibre-Web: Update leads to error

Updating Calibre Web from within the web app has always worked … till now. I just updated the app this morning, and it fails to restart with the following error

[2019-01-29 16:17:41,880] INFO in server: Performing restart of Calibre-Web
/usr/bin/python: can't open file '/app/calibre-web/': [Errno 2] No such file or directory
./run: line 3: cd: /app/calibre-web: No such file or directory

Confirmed by spinning up three other containers from the same image, and updating the same.