Yes. And I verified the numbering settings for each subset folder, and then again for the sheets within the subset. All were set correctly, I didn't actually change anything. However, after verifying all these settings, ArchiCAD started numbering things correctly again. It's odd, but I'm just glad it's working.
Mac OSX 13.6.5
AC27&26, Artlantis 2020, TwinMotion
iMac Pro 2017 / 8-core 3.2 GHz / 32GB RAM