Hi,
I have the same problem as stated above. I upgraded to WP 4.9.5 and WPDiscuz stopped working. Instead of WPDiscus there’s loaded default tempera comment engine.
I tried the hack mentioned above with default form change, but without success.
We are using no caching plugins, so I don’t know which cache I should clear. CTRL+F5 didn’t help as well.
Thanks for help!
Kamil