Having eyeballed them on line, my SWAG is the outer materials (suede leather) became saturated to the point the GTEX lining failed, which is not unexpected with a WPB liner.

I'd clean them then use a DWR restorer or some sort of waterproofing appropriate to the suede. In the future, if you suspect luridly wet conditions, add good gaiters to your kit and I think you'll have better results.

Cheers,