Issue:
ArcGIS Pro 3.6 (and when rolled back to 3.5.5) crash when conducting label operations in numerous existing maps (e.g., making symbology changes within label class window or selecting layers in label view of TOC). None of these maps use the same fonts as the other maps, and many maps only use stock Windows fonts.
Background:
I updated a laptop with 3.5.5 on it to 3.6 by uninstalling 3.5.5 and installing 3.6. I did not do a "clean install" by renaming existing folders. After the update to 3.6, when interacting with labels in numerous existing maps, the program crashed. The font and styles of labels in the maps that crashed in 3.6 had never crashed with 3.5.5. I then did a soft reset on 3.6 (https://support.esri.com/en-us/knowledge-base/how-to-perform-an-arcgis-pro-soft-reset-000027631). The maps continued to crash. I then did a clean uninstall of 3.6 to roll back to a clean install of 3.5.5 (https://support.esri.com/en-us/knowledge-base/how-to-perform-a-clean-uninstall-and-reinstall-of-arcgi-000030419). The maps continued to crash.
I then installed 3.6 on a new machine (different GPU, newer OS version) which has never had any Arc products installed. The same existing maps continued to crash when undertaking label operations and existing maps that I hadn't previously opened on the 3.6 install of the laptop are now crashing as well.
I cannot seem to replicate the crashing in a fresh Pro project. I have submitted error reports, but I have a Personal Use license, so can't submit an Esri case.