8.5.1 Integrated Sametime client loses personal groups

The Sametime contact list in my 8.5.1 client on Linux (but I’ve also experienced this on Windows XP) is regularly losing personal groups, especially those containing users from secondary communities (like Bleed Yellow’s Sametime server).I can then use the Import contact list from server function to get those contacts back but it’s just really annoying having to do that 4 on average 4 days out of the week.

Anyone else seen this behaviour and got a solution?