Ovr bug
My ovr decreased from 109 to 108 when I replaced my 103 ronaldo card with a 109 mbappe card.
Forum Discussion
Ovr depends on ranks too. Did your ronaldo have more ranks than mbappe?
Ronaldo was one rank above
Pictures would be good
From ehat I see, Ronaldo is highest rank (orange) and Mbappe is one lower (red). There are multiple ovr calculators you can use online to check where you stand and what you need to rise.
