Which client did you use to set your private mute list before?

I can think of three possible reasons why it’s not working in your case:

- Jumble couldn’t find your previous mute list event from your write relays.

- The previous client didn’t use the NIP-51 standard to encrypt the mute list.

- You may have denied Jumble's request to decrypt the mute list.

I think the first one is the most likely, haha.