I had a similar issue a few years back and my problem was solved - at the time I was running Campy Chorus and the issue turned out to be the contact under load between the BB bearing and the holding cups - if you have a different BB/crank design it might not help but it's not restricted to Campy and might work if you have a similar setup to Campy , i.e. bearing with cups - the link to my earlier post is below - you have too scroll down a bit to see it .
Creaky Cranks - Bike Forums
Last edited by blinky; 06-19-21 at 11:02 AM.