@Maxym_ShustovI'm not clearly understand how to reproduce the problem. Can you describe the way to reproduce it more clearly?
There are many information we needed:
1. Which version of engine you are using?
2. Which classes & methods you modified?
3. How did you use TileMap?
4. Can you upload the resource files? Or reproduce the problem in project TestCpp?
As you know, we can't reproduce the problem with the code snippet you mentioned.
So it will be much better if you can upload a demo to reproduce the problem.
Otherwise, maybe it's also ok if you can provide more details for us to reproduce the problem.
Thanks for your feedback! And look forward your reply.