I'll take a shot in the dark without pics or a troubleshooting form and suspect budrot.

Budrot will infect and turn colas to mush in a matter of days and may destroy a crop in a week if left unchecked. Botrytis loves warm, and humid (50% or over humidity) conditions. Lowering humidity will slow and stop spore germination. Good ventilation and decent air circulation help prevent infection.

A grow room may smell noticeably moldy if Botrytis has attacked one or more colas. Once a cola has been infected, Botrytis will spread incredibly fast. Entire colas will turn to brown mush and spores will be produced, attacking other nearby colas. Ventilation may spread viable spores throughout the room, as well. Do a search for the term budrot and you will find a wealth of info.

Best of luck to you.