Scott I had had this problem on 2 different 245 wagons. Do you park on a slight downhill incline? Check the cargo window gaskets (rear quarter panel) What happens is the drain holes in the gasket get plugged with silt over time and the water can't drain out, so it takes the path of least resistance and fills up the glass cavity and into the car following the floorboard to the front seat footwell.

What worked for me was to GENTLY probe the front and rear ends of the gasket with a DULL icepick or similar long pointed tool. The channel below the glass is intended to carry off the water at those two points. Insert the DULL tool into the rubber channel and work it front to rear, etc. At the ends gently probe for the outlet holes and you will see the crud come

out. ( you need wet conditions to flush out the silt.)

These wet conditions drove my persnickety wife CRAZY!! It led to mildew problems and trips to the auto glass shops, Volvo independent shop and all they did was make the problem worse. This is a simple fix, it works!!