Weird new aggression behavior from Ma'ii

[Shakou]

So, we're experiencing some weird new aggression issues with Ma'ii that JUST started this past week. When I'm home alone, I let the dog's out one at a time, as we don't have a fenced yard, and walking them together is a pain. When I let Charlotte back in, Ma'ii will growl and snap at her as she runs past him.

Yesterday, I put Charlotte in our bathroom while I was cleaning something, and when I let her out, and she ran towards Ma'ii who was resting on his dog bed under our table, he attacked her. Charlotte was kicking his butt something royal, when I grabbed her and pulled her off. Suddenly Ma'ii turned on me, and came charging out from under the table, teeth barred and snarling. I grabbed him by his collar and threw him in the bathroom and slammed the door closed, and left him in there for a few hours. When I let him out later that night, it was like nothing happened.

My question is why? This is completely new. He's snapped at my husband a few times with jealousy issues, and has had minor squables with Charlotte over food/toys, but has NEVER gone after me. Charlotte and I were both unharmed, and I know if he really wanted to hurt me, he would of. My hand/harm was right there, and this dog's aim is dead on.
Some key notes I feel I should mention:

Ma'ii busted a claw the other night, so my original thoughts were he did this as a result of pain from that, but I doubt that now because he starting doing this before his broke his nail.

Ma'ii has the beginnings of arthritis in his back due to a calcified disc. He is on pain meds, and was given one only an hour before yesterday's incident.

Could he be going blind? He is about 7 now, and blindness is common in ACDs.

Looking for advice and thoughts, please.

 

[CrystalGSD]

The first thing I thought of, even before reading the whole post, was health problems. it could be very much possible that he is redirecting pain towards other things, since he doesn't understand the source of his pain. If it isn't from pain, it could be from blindness, as you mentioned, since he may be confused since he can't see clearly. He may redirect his confusion, possibly thinking that your other dog, Charlotte, was charging towards him.

Of course these are all just guesses. I wish you the best, though.

 

[Ivy]

Maybe it could be some crazy redirection from excitement?? I know Tynan sometimes mildly snaps at others when he's excited during outside time preparation. It's never that bad but I do have to manage it sometimes.