This has happened to me twice now in two different games, and once to someone else on the fan wiki, so I think it bears reporting. Unless you have nerfed Deerclops, which would be a shame...
Deerclops is spawning as usual and stomping around targeting structures, fighting other mobs etc. - but seems completely indifferent to the player! Not that I tried whacking him, because I'm not suicidal, but usually if you get anywhere within sight range he comes after you with a vengeance - and I actually wanted to lead him to my trap field. Suddenly it seems I can run around under his nose and he doesn't care! So I was able to gather materials as he stomped around a forest and even stop to light a nice warm fire... Really not the sort of thing you expect to do in his vicinity!
I'm playing RoG with SW enabled but haven't built the Seaworthy yet. I'm using a few mods, but nothing mob related (Combined Status, Smart Crockpot, Storeroom and Wormhole Marks) and they are all RoG/SW compatible.
Steps to Reproduce
Um... run up to Deerclops and see whether he aggros on you or not? :)
This issue has not been confirmed by a developer yet.