Its a possiblilty it takes time and patience to bleed all the air out
remembering to open the heater valve (or forever  will seem a short time.)
does it have the tower fitted on the RRC to help the process? you could
check the header by running it with the cap off until hot if you get lots of
tiny bubbles suspect the head gasket if it just runs over  more likely an
air lock I usually fill up run for a short while ( not run  to hot), then
remove the highest water pipe ( tower cap) and  fill by pouring down the
pipe, remove the silly plastic radiator plug and top up here as well  pipes
back on run it some more and do it again and after a couple of days repeat
that should sort it

Derek