Temporary workaround for Steam users until the trainer is updated:
Go to RoN:EE in your Library, right-click on it, select Properties, click on the Betas tab (you may need to opt in if you haven't), then select v1_10_old-2014 version in the dropdown box, then click on Enter. This will revert the game to patch 1.10 and both current MAF trainers will work on it. You get the added bonus of it also reverting the changes Skybox made to multiplayer mode, so it's actually mostly stable. Unfortunately you'll get back the bugged sound files and tooltips, but that's better than multiplayer that doesn't work at all (they totally failed to implement Crossplay for Xbox Live properly so it borked multiplayer entirely for PC users in patch 1.20) or going without the trainer.