I just noticed…What is your snippet name? Is it {exec_club}?
If so then it can not have itself as variable, at least not in the last code you posted.
the part of….entry_id=”{exec_club}”
{exp:member:custom_profile_data}
{exp:channel:entries channel="clubs" dynamic="no" entry_id="{exec_club}"}
{club_teams}{entry_id}|{/club_teams}
{/exp:channel:entries}
{/exp:member:custom_profile_data}Maybe a typo?