Hi Giuseppe,
We have analyzed your reported issue with our sample, we could not able to reproduce the reported issue.
We have also prepared a sample with TreeGrid and triggered postback on button click action, after the postback action TreeGrid was rendered properly without any error.
Please find the sample location below.
Can you please share your project or code snippets used for rendering the TreeGrid with detailed explanation, it’ll helpful for us to serve you better.
Thanks,
Suriyaprasanth R.