...ahh yes, the Grid Tool...I've worked around this in the past by creating the Grid System in a New instance of AC and merging the grid into the Project File. I keep this "Grid file" in case any grid elements need to be modified (which is when they seem to loose their settings).
MacBook Pro 2.4 GHz Intel Core i9, 32 GB of RAM
AC25 US (3011) AC24 on Mac OS Catalina 10.15.7