how is my alt account suggesting someone I only know/interact with on my main?

I have two accounts, one alt where I do not follow anybody, don't have contacts synced, it's private, turned off sharing the account to others, pretty much all I can think of. my main account, I follow a bunch of people. and three of which I have their contacts, but I still don't have contacts synced on the account, and I'm not sure if they do either. on my alt, sometimes I go onto the account of one of those three people's alt accounts, but I don't interact, all I do is view the profile, and then exit. I do not interact with this person's alt account on my main account whatsoever. I don't interact with anybody else that I know of on my main account when I'm on my alt. but somehow, the person whos alt account I view, their main account (once again, I have never interacted with, searched, or have any connection to) is being suggested to me. what makes it stranger is that it is only their account being suggested. not anybody else. not even anyone elses tiktok videos or posts or anything at all. there is no connection with my alt and main, other than the fact that someone I know on my main, is being suggested on my alt. is there any way to stop this? does this mean my alt is being suggested to that persons main account?