In ArcGIS Pro version 3.1.2, there is a bug when saving a project to a folder with a comma in its name. For example, saving a project called "GISProjectName" in "C:\users\userName\name with comma, project\content\GIS" inadvertently creates a new empty folder named "name with comma" in "C:\users\userName". This occurs every time the project is saved, and deleting the extra folder doesn't prevent it from reappearing upon subsequent saves. This issue is related to the known bug BUG-000140485.
Is this the same issue - and is there a timeline for when it will be fixed?
As you mentioned, this is a bug certainly and it's in the Product Plan to fix but I do not have a date/ArcGIS Pro release version when it will be fixed. For now, I would recommend not using commas in the name rather an underscore instead.
The bug is still there in 3.4
Yes and still at 3.5 as well as I'm seeing in the internals it's still in the Product Plan to address. Wish I had more positive news about this bug.