I used sniffit to sniff the commands send by irreco. It was a little odd, but I found that when escape key was not working, irreco sent one . too much. Here's a sample of working commands:

And when escape was not recogniced:

I overwrote backend_lib_backend_telnet_la_1.config with manually rewritten same contents and the problem went away.

I also noticed that the added keys disappeared from that file, while I was modifying the remote via the usual gui. But I don't think that I did anything that should had resulted in that... I'm baffled.