Yes, I am running an AV scanner. Bit Defender Internet Security 2010 to be
precise.

I switched off all the AV functions and followed the above steps.

Unfornately, it renders the same result (broken testbug1 repository after
pushing from clone2 to testbug2).

I also did the test with local clones (I mean, clone1+clone2 clone of
file:///....) and it worked well (as expected). I will test again with
hgserve, just to test if something is wrong with my computer. I will post
here the results in a few minutes.