TYPO3 if.isInList not working as expected

I have a simple cObject override which I would like to work if a user is in a certain group. Looking at the TSRef if.isInList should be right for this task? But it doesnt work. This is my snippet:

    if.isInList.data=TSFE:fe_user|user|usergroup
    if.insertData = 1
    if.value = 2

I tested the override itself with a if.value=1 and if.equals=1 -> works fine. I also checked for the TSFE data by showing it as a string, it has the right usergroup in it and looks like this "3,2" ... also this if works but is not good for me since users can be in many groups and i only want to check for one of them:

    if.equals.data=TSFE:fe_user|user|usergroup
    if.insertData = 1
    if.value = 3,2

Thanks for any insights