I included 6 mentions in a post, but after reaching the character limit, it split one of the handles instead of moving it to the next post, i.e.

"...
@gformenti.bsky.social @sergek.bsky.social @arhie.bsky.social @jack-a- (7/8)

medico.bsky.social @mbiegler.bsky.socialerichjarvis.bsky.social @erichjarvis.bsky.social (8/8)"

This happened even after I added two empty lines to the end of the post to create a break point.