Timecode bleeding into preamps of f8n pro

Hello, today I used my zoom f8n pro for the first time on a real shoot. I was going to give timecode from the zoom to one of the cameras. The problem, my boom mic for some reason recorded the timecode sound after I plugged in the cable. Allthough silent, still noticeable. What was even weirder, my lav mic (dji mic 2, reciever connected to my zoom recorder with an adapter) didn't have any of that bleeding. I tried multiple mic pre amps and the result was always the same. So we recorded without timecode.

What did I do wrong? Why did the mke 600 record any timecode sound?