Grant group revoke user isue

Hallo,

version 7.4.7

i first grant a group some privileges,
then i take those privileges away from a user in this group,
somehow this doens't work (no errors, but the rights aren't revoked)

eg:

GRANT ALL ON TABLE test TO GROUP groep;
--the user jimmy is part of groep;
REVOKE ALL ON TABLE test FROM jimmy;
--no complaint, but also nothing is revoked

suggestion, explanations?

tnx,