Many of my friends did autofoam already but have not heard of issues like yours before. Also there are a few foam around now. The one I know is Autofoam from KL Auto. I have seem their foaming done, pillars are all done inside and underneath only the main structure beam is foamed so not sure why got water blockage?
But agree with you that it is not reversible....Once in cannot take out
haha it can get rather scary sometimes....
one example is the lower side sill (below the door) that portion is usually foamed up, it can be an issue if, it is used to drain water collecting at the side sill. This area also has the door switch wire running through it, so in my case, that got burried, thatk god for sate sticks i could push a wire through
(this particular case, maybe can be considered to be unavoidable unless someone maybe uses a straw like a protective pipe? (silly idea anyway)
On some cars with a sun roof, sometimes they have a drainage hose running down a pillar (on the preludes, its the front driver side A pillar i think) somehow that fellas pillar got stuck