Toilet leak from side

Hey folks! I have a new toilet (2 years old) and it has slow leak when someone is sitting on it and flushing on the side.

I changed the wax ring and it still was leaking. I hired a plumber who added another wax ring and couldn’t tell me why it was still leaking! He claimed it’s cuz of microcracks in porcelain toilet but it’s relatively new.

My cousin said it could be because it’s an older house (1924) that is may be off balance with settling and recommended a foam ring as his house had same problem.

Would anyone have ideas or recommendations on foam ring or any idea why it would be leaking? The plumber said the flange was intact and looked solid.

Thanks so much!!