I'm currently standing next to a "profession: Jam Guy" villager that has both trades involving jam and completely uncharacteristic trades involving railcraft tracks and such. The villager initially spawned with trades from the right group, but when I unlocked tier II, the new trades were.... different, and not in a good way. I've also encountered a jam villager who has ONLY railcraft trades (for which he earned the nickname & name tag "traveling jam merchant"). If you guys (addressing both development teams) could work this one out, I would GREATLY appreciate it, as I want jams :-/

By nature of this issue, it's hard to tell which side of the fence the problem lies on, so I've taken the liberty of posting a nearly-identical issue on both mods' issue trackers. You can find the sister issued to this one HERE

Does it happen only with these 2 mods? I think it is caused by coremods.

That very well could be, especially since one of the mods in play is SpongeForge. I'll do some experimentation and let you know.

I don't think SpongeForge is the criminal though. Can you provide a list of mods for your server?

And by the way, does it happen with any other mod's villagers?

Okay, it appears to not be limited to villagers from either mod, and it only seems to happen on my spongeforge server, so I'm opening an issue SF's github. I guess you guys should close your respective issues for now. See Spongeforge #1562