@Craven de Kere,
That's part of the validation imperfection. I think there's just a simple brute 5 tag , x characters or combination of both used. You are triggering it but the message is not very clear on what you are hitting.
We will need to address both.
Hey - I discovered something else that is probably relevant.
When I click in the text box above the "tag topic" button, one thing that always struck me was that the cursor gets to be in the middle of the box, rather than on the left. Out of sheer analness, I usually click backspace to get it to the left, type in the tags I want to add and click on the button. Seemed wholly inconsequential.
But now I chose a thread that already had a couple of tags in place, and tried hitting Ctrl+Shft and the right arrow, highlighting the empty space in the box. Because that's what it did; unlike when there is nothing there and clicking the right arrow does nothing, it started highlighting empty space, suggesting there were tabs or spaces. And lo and behold, when I went on far enough, one of the existing tags showed up! Still clicking the right arrow, I highlighted that tag, more lengthy empty space, and then hey, the second tag!
OK. So this appears to have something to do with the problem I had, where when I added new tags, some would go up, but then others that had been up already would disappear. When now, I highlight the empty space until I reach the existing tags, leave those in place
(while deleting the white space) and type in the tags I want to add at the very end, I dont seem to have any more existing tags disappearing.
Now the remaining problem seems to be what you mentioned, that when you reach the max number of tags or characters, it seems to cuts off the tags. There seems to be some inconsistency, sometimes it just accepts three tags, sometimes five, and just now i tagged the "McCain lies" thread with eight tags and they all went through. Whereas a couple of times it refused my tags altogether when I put in, I guess, too many. But some of this might be user error as well - I'll keep trying..