Basically the title. When Utilitarian is installed along with Quark, if you try to craft slabs back into planks, some wood types will give you logs instead, as seen here:

I first noticed this in All the Mods 9 (and it was reported to their Github here), where the only vanilla log types not affected were birch and jungle. In the instance I took the above screenshots in, birch, acacia, and dark oak are affected, but the rest aren't (this also seems to vary from launch to launch, even with no changes to the instance. On one startup, oak, acacia, and mangrove were the only ones unaffected)

Testing with just Quark, Zeta, and JEI installed, it behaves normally, giving planks for every wood type. Once Utilitarian is added, I start getting this behaviour

Based on a comment in the ATM 9 issue linked above, Quark is using the first 1x3 block to slab recipe it finds, then is working backward from there, but I don't know if that's correct or not

Mod versions (all are the newest as of posting):

Forge - 47.2.20 (but also tested with the newest 47.3.5)
Quark - 4.0-458
Zeta - 1.0-19
JEI - 15.8.0.16
Utilitarian - 0.9.1

latest.log - https://mclo.gs/uQphauW

I've had a look into this and it seems this is caused by Utilitarian's logs to slabs recipe, which returns 24 slabs. This should be easily fixed by adding a check to this method to ensure the output of the slab recipe returns 6 slabs. I'm not very familiar with Java projects let alone Forge mods so can't guarantee I'm not overlooking anything, but I'll see if I can get a pr in none the less

I've had a look into this and it seems this is caused by Utilitarian's logs to slabs recipe, which returns 24 slabs

Yeah, that lines up with what I found as well (I mentioned it in the OP, just above the versions). Hopefully, your pull request is able to fix it