UKPassats

When on the intermediate cruise control setting (I.e. the speed is set but you’ve touched clutch or brake so it’s inactive) I noticed today on two occasions that the car seemed hesitant and the revs jerked up & down for a couple of seconds.
Happened in both 5th & 6th gear at about 1900rpm.
If I turned cruise off or just accelerated myself it was fine.
Anyone felt similar?