Just for fun I ran WSJT WSPR on 30 & 20 to see what was coming in. Weirdly I get identical stations and signal reports on both bands. However FT8 does not so this. Running 2.4.9, Slicemaster v0.10.6b and WSJT-X v2.0.1 7ddcb7
Did you start wsjt-x on different config directories, Zack? Each instance needs to be started with the command-line option to start on a fresh configuration set (directory, actually). My apologies if you are already doing this - I have no intention to insult your intelligence.