xuran hmm there could be a few reasons for this
make sure you know the difference between position
and global position
I'll probably explain it badly so i'd recommend researching the difference yourself, but the summary is that you might be using position
when it should be global position
or vice versa
I'm guessing the Instance is being placed as a child of the Tilemap so it'll use it's parent's position instead of the correct global position
anyway hope you solve the issue