Potential roof leak or mold?

Hi All,
I recently moved into a brand new house, a few months later and I noticed a few mushy spots in the ceiling, it's soft to the touch and only noticeable in one corner of the bedroom as per the photos. I've never seen it dropping water or something like that, seems dry to the touch and only in one or two spots.

Do you know if this looks like a water leak or potential mould? and if it is something I need to address, who should I contact for repair?

Thanks in advance.

 

Contact the builder, raise it as a concern that it may be a leak (not a it's stuffed and I want it fixed today) conversation.
If you didn't buy direct from the builder then there should be some form of contact details in your purchase contract
Yes, it will be covered/warranty.