Issue Summary

In some cards @ mentions in the card description aren't being formatted properly

Instead of showing @username they're being shown as @:123456 with the ID of the account that's been mentioned.

This prevents any users viewing the card from easily knowing who has been mentioned in a card.

This problem was reported previously in a separate bug report (TRELLO-611) and has been fixed, but one customer keeps seeing the problem come back in two boards. I'll add the links in the comments. I discussed the case with the dev team, and even though it may be related, it's probably a different problem, so we're opening a separate bug report.

Steps to Reproduce

Have been unable to reproduce so far

Expected Results

See the username when tagging a user

Actual Results

After a while, the usernames are replaced by the IDs

Workaround

None.