we're using zarafa comunity edition and got the following problem since a few weeks:

Some of our Clients (all Mozilla Thunderbird) produce high load and cpu-usage of zarafa-server.

I increased the log level in zarafa-server and got the following message about 20 times a second:

When i stop zarafa-ical (need to kill it with signal 9), cpu-usage drops imediately. Our user has the following client / settings:

thunderbird 3.1.7
lightning 1.0b2

Any help is appreciated.. thanks in advance,