Is it obligatory to re-fast the ten consecutive days, after vowing to fast them consecutively, and having fasted some of them intermittently?

The questioner is advised to disregard the whispers and not pay attention to them. If he doubts the intention of consecutive days for the vowed fasts, then this doubt is as if it doesn't exist. The default is no intention of consecutiveness until certainty is achieved. And whoever did not intend consecutiveness is permitted to fast the days separately according to the majority of scholars. Therefore, he is not obligated to repeat the five days he fasted non-consecutively.