I tried to address a comment on this entry to Isaac using the @ notation. When I typed @ and started to type his name I didn't get the usual hover suggestion, and when I typed it manually anyway it was stripped from the posted comment. I think I've seen this occasionally before, but it feels non-deterministic to me -- I'm pretty sure I've addressed Isaac before, both on main and meta. Any idea what might be causing this? Is it me, the particular entry, Isaac, the phase of the moon, something else?
This is by design. As Rebecca Chernoff explains:
If comments are only between you and the post-owner, and nobody else is commenting, then an @lert to the post owner at the beginning of a comment will be removed.