To reproduce: start server game -> connect with client -> build depot -> create new convoy -> click "schedule" -> click "copy convoy"
the error "unfinished/incomplete schedule" will briefly appear before losing synchronisation with server.
for whatever reason, this does not occur on standard.
Thank you for your report. I believe that I have now managed to fix this. I should be grateful if you could re-test with the next nightly build.
Thank you, this now appears to be fixed.