TOC books display last topic in previous book when clicked

I have found some slightly wierd behaviour when looking at the output published to RH Server 8 from a RH8 client and using a merged help file set-up (although the merged project set-up maybe irrelevant). Clicking on any TOC book displays in the topic pane the last topic in the book immediatey above it. In the example below, focus in the TOC is on the "Basic Tasks" book and the topic displayed is "Managing Tabs" which is located immediately above the book. No matter which book is clicked, the same behaviour ensues.

This problem is limited to when the help is displayed via the RH Server eithere by clicking on the "View Project" button in the Web Administrator or displayed via the application. Bizzarely it does not occur if you manually open the start page in a web browser from the RH server. Neither does the problem manifest itself using WebHelp output.

Has anyone seen this. I'm tempted to report this as a bug but thought I'd float it out there first.