Temporary workaround for me is to use
dconf read /com/ubuntu/user-interface/scale-factor
to read the value when the setting is still correct, then copy the output and assign it back with
dconf write /com/ubuntu/user-interface/scale-factor "{'DP-6': 16}"
Note that this dconf value gets resetted every time this bug happens, so you have set it again. Anyway I find it faster to just have it as a command.
Temporary workaround for me is to use
dconf read /com/ubuntu/ user-interface/ scale-factor
to read the value when the setting is still correct, then copy the output and assign it back with
dconf write /com/ubuntu/ user-interface/ scale-factor "{'DP-6': 16}"
Note that this dconf value gets resetted every time this bug happens, so you have set it again. Anyway I find it faster to just have it as a command.