Omnia + TOS 6.0 (HBL): Switch configuration broken

I have clean-installed latest HBL through medkit. I have noticed that even completely out-of-the box (just after setting password and skipping guide to enable wan connection), the br-lan switch/bridge behaves very weirdly: With Wireshark on a computer/interface connected to the switch, I can see I receive packets with internet destination (and destined for br-lan mac address) originated from computers connected to other switch ports (not the other way around, though) - I certainly shouldn't see those! That being said, everything works, so it seems that everything destined for the bridge mac address is just being sent to every port. Changing br-lan MAC doesn't help, unfortunately.

Everything seems to work otherwise, I only noticed that when sniffing traffic. Seems like something is broken with the DSA switch config.