Strange glitch

I think this issue reported on Github is describing the same or a similar problem. There doesn't seem to be a solution yet.

https://github.com/mybb/mybb/issues/2815

Yes, that sounds like it. From the description, it seems it only occurs if normal users and guests can see deletion notices. Is there any real advantage to being able to see deletion notices (apart from reassurance that one is not going mad when a post disappears)?

Sorry if it means I've screwed up that thread by posting and deleting test messages.

Don't worry about breaking anything. Yes, I don't think there's really any great benefit in seeing the "deleted post" message. I've switched that setting off. Maybe you could check to see how that thread looks now.

Thanks. It looks OK - and better without the deletion notices, I think.

[Laird]

Yes, I don't think there's really any great benefit in seeing the "deleted post" message. I've switched that setting off.

Have switched that setting back on due to the benefit described here; namely, consistent post numbering for all members. Whether or not having this switched off had fixed the glitch in the first place, it no longer seems necessary given that, as indicated at that link, most members have been seeing post deletion notices for a long time now without further reports of glitches.