So far, I've had 100% (5 out of 5) of my 90 day reports approved by Buriram IO, when using the "new" online 90 day reporting website which was implemented in December 2021. Prior to that, I have had all my 90 day reports since the system was first implemented in April 2015, (that I have been able to submit) successfully approved using the "old" website.
The times when I could not submit a report were when:
1) The immigration extranet was not available (For various reasons)
2) I got a new passport
Once I left Thailand and entered using my new passport, I was good to go again.
I guess I'm one of the lucky ones.