Which controversy ? (Apart from unproven, half-lunatic ones)
Not that likely, anyway : Portuguese followed the road to Indias by Africa, meaning it was hard to get lost; loosing sight of the coast would have prevented them to go too far westwards.
You'll argue that Cabral did it but he wasn't a really good navigator (being probably nominated for political reasons) and when they realized it wasn't Africa or Indias, they left.
Now, an earlier accidental discovery is possible, but Portuguese would probably consider it as "not Indias new land" and not give it too much importance in a first time (maybe as a stop on the road, but it was quite far from it. Eventually using it as an Azores-like land (for sugar) pretty much as OTL happening earlier with consequent changes.