For me it seems to work normally, except that following every cloud sync the list of transactions belonging to the group becomes dereferenced. To help me know which transactions to re-add, I altered their entries in the memorized transaction list by prefixing each transaction in the group with "Group N:" (where N is the group number).
This dereferencing has been occurring on for a good couple years now.
I think I've proven this by creating the group transaction on the Quicken web app. Following a cloud sync, the group transaction appeared in the Quicken app and has remained there for several cloud syncs now.
If the use of Scheduled Transaction Groups for banking register transactions gives you problems, …