Is Facebook spying on Tiktok?

A few years ago when I signed up for tiktok, I made sure I didn't give it access to my contacts or to any of my social medias. In the last few months I came to realize that most of the creators that I follow on Tiktok are strangely appearing in my FB reels/wall even though I don't follow them on FB... anyone is having the same issue? Is Facebook spying on tiktok just to keep me (us) on their platform?