Unlock Target

Your husband must be pressing the left stick; this is what turns on target locking. Once target locking is on, you can also press the left stick again to select between different available targets.

It shouldn't be locking on to items though, I'll take a look at what could be happening there. 

Sorry I'm late getting back here. Thank you for your response. Obviously, the left stick is used to move throughout the game, and we can't see how pressing it in any manner turns on/off locking (we've tried - is it a "visible" option?). He can be walking somewhere, attempt to pick a carrot, and he cannot do so because he is locked on a flower he passed by a full screen ago. It seems odd this only began happening with the Halloween update. We switched controllers, but he still has the same problem. We've been playing together for over a year now, and the biggest problem for me is that this results in some colorful language coming from his side of the room.

Target locking was added with the Halloween update as a way to improve combat. It is activated by pressing (clicking) the left stick. Your husband is probably doing it unintentionally while he's controlling his character. It should only be activating if you're in combat though, and only locking on to enemies. The last update (Winter's Feast) included a fix to keep it from locking on to targets as actively as it had been.

Ahh ... that explains why we think it happened with the Halloween update.   I tried messing around with my controller, and eureka!, I was able to push on the stick and lock on targets. We've come to the conclusion that my husband has the "problem" and I don't, because he has a heavier hand on the sticks ... and his controller is old and may very well need to be replaced. Thanks for looking into this and adding a fix. I think we'll be ok going forward.