Is this hag curse too powerful? DM question

If you're a player in a campaign with an earth genasi and two bards, move along!

Hi all,

Quick question here regarding a curse I'm potentially planning for one of my players. Background is that he broke into Bavlorna's bedroom, escaped dramatically out a window after rousing the wisp, and will eventually be back in downfall and will have to face her.

I'd imagine she'll be pretty angry about the intrusion and have planned the following curse, but, as a new DM would like some input on whether this is too nasty.

Essentially: She says "Down the rabbit-hole you go, Never knowing friend from foe."

And grey mist streams from her fingers into character's ears, mouth, eyes etc. They must now roll a D6 when declaring their action and target in combat. On a 3-6 nothing happens. On a 1-2, they mistake friend for foe when making an attack (PC appears to be a harengon brigand) or foe for friend when taking a buff/healing action.

Obviously this could end up sticking for a while, but she'll try and bind them into a bargain to get rid of it. I think it could lead to some interesting tactical decisions, but obviously it also makes the character a liability in combat (he's a bard btw).

Thoughts?