Not an earthshattering issue but when applying a new recurrence to a task by month, the default value of 'number of months' is not 1 but n (all the other frequencies are 1 as expected).
n changes!: I'm guessing this value is being picked up from the month field of the item - e.g. for start/due date in June n=6-1, in Sep n=9-1.
Thanks,
Jon