Stem is rotting veg state

[SoD4nk]

A lot of my veg plants stem is rotting and snapping.. I had 19 vegging plants.. Only like 10 survived.
When I transplanted they snapped. Is this sign of pests or fungi? My veg room does get a bit chilli since it has no heat in there and only thing that warms is up is my lights. My thermo read the lowest has 65.
My other 7 flowering plants didn't do any of that but it was also during the end of summer when they were vegging.

 

[Chemdog1989]

Look up damping off. It's probably from over watering. And it being cold doesn't help with plant uptake and evaporation. But it's not from the cold.

 

[DurumGallico]

Look up damping off. It's probably from over watering. And it being cold doesn't help with plant uptake and evaporation. But it's not from the cold.

cold can prevent the soil from drying, and can lead to mold issues. I think over watering + cold is the issue