Thank you very much for the report and I am very sorry about the issue! I tried to replicate the issue using Archicad 24 INT 6004, but it works correctly in my case. May I ask which Archicad language version you use, and did the issue happen with the latest update installed?
Thank you very much for the information! This is very helpful!
I found that, with the default AUS template, the option Uniform Window Surfaces is enabled. This is the reason why the surface got changed when you set the ID. Seems like this attribute was "reset" to match with the other surfaces set in its settings. Thus, the workaround in this case is to disable Uniform Window Surfaces option
I believe this is a bug, so I will enter it into our defect database. Thank you very much for the report once again, and have a great day!