[Muesrasrs]

Asalaamu Alaykum wa Rahmatullah,

If a few people start reciting the Khutbah with the Imam allowed (obviously not saying it loudly, but loud enough that you can distinguish that a group of people are speaking along with the Imam), would that invalidate their Khutbah?

I've noticed this a lot in my local Masjid, Especially when the Imam has finished with the dua and is concluding his Khutbah; many people begin to very quietly recite the last few lines with him in unison.

JazakumAllahu Khairan for your help.