I had this problem, and it was definitely a theme issue.
https://askubuntu.com/a/1372318 may be helpful in setting a theme just for libreoffice, it you’re using GTK themes. (Basically, override the GTK_THEME variable in the .desktop file). I haven’t tried it myself since I just switched to a different theme.
When you say you changed the channel, are you using a channel above 11 (for 2.4ghz)?
I had a WiFi card once that refused to use channels 12 and 13 due to having a built in regulatory database that was incorrect for my region.