Verified answer

maybe you should ask a real Jap about this one... sorry

Actually, your example doesn't make sense.

Anyway, the case you use を after 瞬間 is when 瞬間 is treated like an object.

For example,

この瞬間を楽しもう (= let's enjoy the current moment)

犬がジャンプする瞬間を撮った (I took a photo of my dog when he jumped)

When に comes after 瞬間, it usually means something like "at the exact moment" or "in this instant of time."