Issue with mention of user that doesn't belong to a private repository

Why I was trying to ask a question about a post and a delete annotation in our codebase because i didn't put ticks around the annotation bitbucket mentioned users that don't belong in our private pr.

Steps to reproduce:

1). Create a comment
2). Insert @Post and @Delete without the ticks
3). Bitbucket printed {{@}}Dennis and {{@}}Frantisek