Must prayers that were combined be repeated because of continuous passing of gas without sound or smell?

Ablution is required when the emission of gas is certain. However, if it is merely a misgiving (waswas), it should be disregarded.

If gas emission is continuous throughout the time, the person performing ablution (mutawaddi'ah) should perform ablution for each prayer after its time has begun. With this ablution, they can pray the obligatory (fard) and supererogatory (nawafil) prayers. Their ablution becomes invalid when the time for that prayer expires, according to the majority of scholars.

Ablution is an act of worship, and there is no harm in performing it. If someone prayed 'Isha with the ablution of Maghrib, believing that ablution is necessary for each prayer, they have sinned and must repent and make up the prayers.

It is not permissible for a legally responsible person (mukallaf) to undertake an action without knowing Allah's ruling concerning it. If that action was based on a permissible fatwa, then no making up (qada') is required.