Fermentation ... no, should not cause any problem in the actual fermentation.
But when Ascorbic Acid is oxidized, it produces hydrogen peroxide (H2O2)... an even quicker oxidizer than O2.
However ... Hydrogen peroxide will react with any SO2 (actually, any “free” SO2) ... and will become a stable compound thereby halting some of the oxidative effects.
Use adequate metabisulfite additions when ascorbic acid is present.
Ascorbic acid is mainly suspected as contributor to long-term oxidization ... and so, some winemakers are avoiding it’s use.
While that is an issue of longer term storage, ascorbic acid IS used in the wine industry as a *short*-term anti-oxidant (it has the ability to rapidly remove oxygen from juice and wine) however, like I say later on during storage it can act as a pro-oxidant.
So if yer going to drink it soon ... ascorbic should not be a problem. Otherwise ... make sure you have enough free SO2.