Error when saving masteries, results in having no masteries. Very replicable (unfortunately)

In new draft champion select screen, there is a frequent bug that occurs when you create a new mastery page from scratch and attempt to hit SAVE. A textbox explaining an error will come up and it will act as though the mastery page has not saved, even though it does. Only fix is to name the new mastery page after the error or else it will treat it like you have the page setup selected but you will always go into game with no masteries (and it is a huge bummer). This has happened to me about 3 different times and in my specific cases, I delete a mastery page to make room, then I create new, and it saves, usually as Mastery Page 20(20). However, as I mentioned, it will have an error textbox explaining that an error has occurred. I will double save, triple save, and if I do not name it but still select it, I will have no masteries.

Please fix.