The foam is caused by the gradual wear down of the insulation in the ac/heat system. Everybody who has a 996, also has foam flying out nothing to worry about.

Thanks

There are multiple threads on this. More common in hot humid environments. It is the foam covering the various mixing flaps.
See this one:

https://rennlist.com/forums/996-foru...nt-debris.html

Yup the air deflection doors have foam on them to seal. The foam deteriorates And over time blows thru the dash vents! I had this issue and now my AC comes out of the defroster vents and dash vents! Since the AC air discharges out of both places, on a hot humid day the area of windshield above the defroster vent fogs up. The only fix is to fix the foam on the directional door! No sure how much that costs.
There is a fix on the net for a Boxster but not sure the access point to get at the door is the same on the turbo.
Eventually the foam discharge will stop. I removed the side vents a few times and used a shop vac to keep the vents clear.

Boxster hack works. Heater core is in the same place.
There is also a write up on here somewhere.