Forum Made Simple - Access Denied error when deleting topic

[WeeJimmyHat]

I'm running CMS Made Simple 1.6.3 + Forum Made Simple 1.9.4

All working well except a couple of things (I'll post them in separate posts).

My client is getting the following error when trying to delete a Forum topic:
'Access Denied. This is a private forum'
But the forum topic does delete. It's just confusing for my client.

Basically the same issue reported here: http://dev.cmsmadesimple.org/bug/view/7852

It happens every time, whether there is one post or more than one post in the topic, and whether the same administrator who started the post is doing the deleting, or if a different administrator tries to delete a topic started by someone else.

Any ideas/help gratefully received.