Bottom of bump gone soft?

Willow

Can anyone shed some light on why? I’m 39+1 and I’d say the last 3 or 4 days my bump below my belly button has gone soft, like flabby, it did have a bit of a belly pre pregnancy and it just kinda feels like that allow the top is still hard. I would expect it to be the other way round if baby is getting lower at this stage. Any info would be greatly appreciated TIA