Thanks, we'll try to reproduce the issue. Re: your question, statistics is built when you load a fresh database with db create and optimize it later after updates with db optimize (though it can be disabled for the latter with -o optimize.statistics=false). If you simply start the server, it should not rebuild statistics.
I must add, however, that selectivity statistics is the main source of information for the cost-based query optimiser so disabling it like that may have negative effects on query performance.
Cheers,
Pavel