When I synchronise my calendar in Thunderbird, events sometimes get multiple entries in my Lightning/Sunbird calendar. I.e. I see the same event, say three times after synchronisation. Strangely this doesn't happen always and I have not yet been able to recognise a pattern behind this behaviour. However, the bug is reproducible in different accounts. I use the latest version of the plugin, i.e. v0.9.1
I've attached the log (note that I've deleted part of all occurrences of my IP address, so this is intentional).
Funambol plugin log