new post icon stays on

[Onyx65536]

I have one main board where the new post icon doesn't change even if you've read everything. But it only happens on that one, others work fine. It's done this for months despite upgrading and changing mods etc, any ideas on how to fix it?

[Kindred]

URL?
SMF version?
Mods installed?

[Illori]

are the posts made in that board directly or in a child/grandchild board of it?

[Onyx65536]

I get this sometimes if I run "find and repair any errors":

The following errors are fouling up your forum:
Member #0 has marked one or more boards as read, but does not exist.
Would you like to attempt to fix these errors?

I did this and after several minutes it started working properly again, made a few test posts to make sure. I remember doing some maintenance thing in the past that temporarily fixed it, maybe that was it.

I'll see if the problem resurfaces, if it does I'll post back. Here is the info in the meantime, thanks:

URL: hxxp:orderoftheserpent.org/forum/ [nonactive]

SMF 2.0.15

Bookmarks 2.5
Group Attachment Limits 1.1.0
Move Topic Notification 1.2
SMFPacks Mentions 1.5
SMF Gallery Lite 5.6.1a
SMF Gallery Pro   7.2.2a
Post and PM Inline Attachments 5.7
Play Media Attachment 1.6
SMFPacks: SEO Pro Mod 2.3
Simple Audio Video Embedder 4.0.3
SMFPacks Personal Conversations 1.0.5
SMFPacks Shoutbox Pro 1.1.6
Soundcloud BBcode 1.7
Socialize 1.8
Like Posts 2.0.5
SMF 2.0.14 Update 1.0
SMF 2.0.15 Update 1.0
Board Index Unread Icon Fix 1.0

[Onyx65536]

are the posts made in that board directly or in a child/grandchild board of it?

The board in question (Lounge) has child/grandchild areas.