I have the polls application installed since a long time and using it with our sports club.
Now when I did an upgrade to nextcloud version 20.0.11 from 20.0.9 I ran into a problem.
The log says:
"Message":"Too few arguments to function OCA\\Polls\\Migration\\FixVote
and the updater stops working. I had to remove the folder/app.
When I retried to install 2.0.5, the same error (now at nextcloud 20.0.11) appears and I had to remove the folder again.
Now I switched back to polls 2.0.4 and everything works fine.
So 2.0.5 seems to be broken