Eleven Moon Phases in Folio 86v?

[Dobri]

I no longer know where it belongs. It was a long time ago.

That's the ‘V’ with cloud where you were looking.

This is not the same with the Beneventan flying sideways 'm' resembling the Arabic numeral '3'.

In the illustration you provided, the flying 's'-like symbol above 'V' is an abbreviation for 'Versus' but not 'Um', see an example below from "The elements of
abbreviation in medieval Latin paleography" by Adriano Cappelli.