mouse locks DIGNITAS PRO5

well, yesterday my et started to stop getting mouse input for a very short time every 1.5 sec
not only movement stops, sometimes clicks are ignored too

i am using mx518 with logitech drivers
in every other application it is ok, including q3
tried in_mouse 1\2\-1 and a in_restart after it
its not pb, effect is noticeable even at main menu, etpro\etmain doesnt matter too