Not sure what is going on but you are not alone:
The sorting works for me on iPad (16.3.1) and macOS (Ventura 13.2.1) but I am on the earlyaccess update branch, so a bit newer Roon versions than you may have.
I’d still make sure that your versions are all up to date on all devices. This is what you should have:
Build Numbers
Application | Version |
---|---|
Roon / RoonServer | 2.0 (build 1211) production |
Roon ARC | 1.0 (build 145) production |
Roon Remote (Android / iOS) | 2.0 (build 1211) production |