Did Ambrose of Milan consider Mark 13:32 a textual corruption?

I came across this striking comment on Mark 13:32: > 192. It is written, they say: But of that day and that hour knows no man, no, not the angels which are in heaven, neither the Son, but the > Father only. Mark 13:32 **First of all the ancient Greek manuscripts do > not contain the words, neither the Son.** But it is not to be wondered > at if they who have corrupted the sacred Scriptures, have also > falsified this passage. The reason for which it seems to have been > inserted is perfectly plain, so long as it is applied to unfold such > blasphemy. https://www.newadvent.org/fathers/34045.htm Ambrose seems to suggest that this verse was a later corruption or interpolation. My question: How should one respond to such a claim in an apologetical setting? Does Ambrose’s statement reflect any known textual variant among the extant Greek manuscripts, or is he simply making a theological argument against Arian interpretation?