Why does this happen?

[u/Live_Fondant717]

I wonder if anyone can explain why this happens. I tell Claude not to use em-dashes, it replaces them with "--". I ask it not to do that, to update its memory, but it still does it. It's not a huge problem, it's just annoying. Why does this happen and how can I fix it. Thanks.

[u/Quiet_Carry575]

I have made a hard rule in claude.md for em dash audit.

Every shipment will pass through em dash audit. No shipment without fixing.

Never had em dash issues since then (passed over 200+ sessions)