Thank you using the Bug section, using templates provided will greatly help the team reproducing the issue and ease the process of fixing it.
Are you using Developer Mode or made changes in it?
yes
Brief description of the issue:
While cruising on FL350 with STD QNH, my displayed altitude on IVAO is 33291, despite the following reported fix on SU9 release note " Corrected error in ISA pressure formula application to weather atmosphere that was causing errors in the QNH to pressure altitude relationship, especially at high field elevations"
Provide Screenshot(s)/video(s) of the issue encountered:
The SU9 release note you quoted has nothing to do with your reported issue. You are at FL350, but IVAO is reporting your true altitude, which is 33291 (or actually 33285 according to your screenshot). There is nothing wrong there.
As there are other bug reports on issues with altitude on 3rd party ATC networks, this topic was closed. Please contribute there instead, as this issue does not seem to be IVAO specific.