Does the prayer become invalid if a Muslim performs a pre-emptive prostration (sujood qabli) in the place of a post-emptive prostration (sujood ba'di), or vice-versa, knowing that there is a difference among the madhhabs regarding the ruling on pre-emptive and post-emptive prostrations?

Scholars have differed on the timing of the prostration of forgetfulness (sujud al-sahw): Al-Shafi'i held that it should be before the salutation (taslim), while Abu Hanifa held that it should be after it. Malik said that if its cause was a deficiency, then its prostration is before the salutation, and if it was an addition, then its prostration is after the salutation. As for Imam Ahmad, he held that it should be before the salutation, except for what has been explicitly stated to be after it. Nevertheless, the prayer is valid whether the worshiper prostrates before or after the salutation.

Regarding the glorification (tasbih) in prostration, it is, according to the Malikis, among the virtues of prayer. And whoever performs the prostration of forgetfulness before the salutation for intentionally or ignorantly omitting it, their prayer becomes invalid according to them. However, some scholars have permitted prostration before the salutation for omitting the glorification in prostration, and it is permissible for the layperson to follow this opinion.