Continuous memory growth without tcp.bro

Without tcp.bro the memory footprint of the Bro process increases until it
reaches the memory limit and Bro dies. I conducted the following tests:

1. bro -i eth0 profiling.bro
2. bro -i eth0 -f "tcp" profiling.bro
3. bro -i eth0 -f "tcp profiling.bro tcp.bro
4. bro -i eth0 profiling.bro tcp.bro

Only test 4 didn't result in outrageous memory usage. Obviously the
capture-filter preventing the processing of data packets is the reason. But
I'm curious, what exactly does Bro store when processing data packets that
causes such a memory bloat? I would have figured the processing of data
packets only results in updating pre-existing connection state objects. Is
there any way to prevent this bloat without modifying the source code?
Thanks,

Eric

So, I've (finally) tried this and Bro runs fine for me; memory stays
stable after some time.

Which Bro version are you using? Can you send me prof.log?

Robin