How come? RE matches, but does not set $^R

Hi all, Assume the following REs: /(B(?:=c*))(?{'got B'})/ /(B(?:=c*)?)(?{'got B'})/ Both expressions match as expected (and set $1), BUT: the second one does n o t set $^R as it should do. However, if I say /(?>(B(?:=c+)?)(?{...})/ i.e. force Perl to eat up anything it matches, $^R is correctly set.