Hmm, now the bug is gone though I remember how it was. That's the compiled release binary, 0.3.12 as I already mentioned. I didn't use -connect. Flickering was fast from 0 to 2 (less than half second) and then there was a pause in about a second with 0 connections. So the flicker itself was almost every second (not faster). Looks like it got connrefused instantly or such. I watched logs, sorry didn't saved them but there was nothing interesting just connect and disconnect without a reason.
I measured the RES memory with htop. It updates once per second that's why I can't see the real leak speed. Now the client tries to connect after startup and flickers 0-2, too, but just 5-10 times and then establishes one connection. Then it flickers between 1 and 3 and no leaks happen. Then connection number grows up to 40 or even more, everything is stable. To reproduce this try to switch off the network connection right after the client gets IPs from IRC so it will try to connect and fail.