Sorry Terion for the late reply (You should really join the discord

) but I managed to figure out what was happening with my replays.
I've had installed a second version of WA (GOG) to test on and didn't realize it had associated all replays with
that version of the game, which didn't have the terrains in its files.
This was the cause of all my replay weirdness and is fixed now, no fault of the module.
To anyone who wants to try the themes available now check out:
https://worms2d.info/WkTerrain