Moisture in headlights

[my911e]

My 2000 540i is getting moisture/condensate in the headlights.
It started about a year ago on the driver side.

My shop disassembled and blow dried the unit and cleared vent holes.

Last week they repeated it, but now on both sides.

Today they are "misty".

What are we missing?

How to prevent condensate, like during the first 12 years?

HELP?.... Instructions?

Thanks