And yes, I have heard that it's taboo to thank certain types of wights, particularly the Celtic variety, such as fairies. I try to refrain from thanking them too much, if at all. Simply because it seems like bad manners to thank them for things they like to do. I've heard someone on a thread once say that it can make it seem like they are obligated to do things for you, or that they're doing their job just to satisfy you, which understandably can be offensive to some of them. But honestly, I see little problem in thanking one occasionally once you have a good relationship of respect & trust - although that's just me.
I've come across this as well but not regarding house wight/spirit. If you believe in the literal fey/Sidhe then they're quite a different horse from a land wight or land spririt (though likely kin) and I would think that just as thanking them (implying a superior status, I.E. thank you waitress) would be offensive treating them as *your* wight/spirit would as well. I've also read that expressing gratitude such as complimenting the gift etc is perfectly acceptable.