I've reproduced this on XP with both Chrome and Firefox.

For you to reproduce it:
- you may need to use the platforms above (I don't know if it affects others)
- view a locked thread where one poster is on your ignore list
- on that post (posted by someone on your ignore list), click on the "view post" link. It does not work and cannot be made to work, even by right clicking and viewing in a new tab or stuff like that.

What it does do:
- It opens a new tab with the same thread shown, and the same post blocked (as per your ignore list settings).

Why its a bug:
- because the "view post" option is designed to "go around" your ignore list and allow you to see the post anyway.

Priority to fix: (imo): Low, because workarounds are easy. I almost didn't report it even.