Just thought id update on mine:
After this happened in Dec, we had a dryish spell and it hadnt happened, untill we had all the snow last week, when that melted i had the light problem, it also went on to effect the Temp, fuel and MPG guage (all registerted 0 when driving) - then the final straw was the alarm!
I unlocked the car with the fob, and opened the door and the alarm was set off, and it would not go off no matter how many times I locked and unlocked it with the fob. Eventually it stopped, so I tried again, and it set off again! This time i just got in and drove, 100yrds down the road it stopped and didnt do it again, however the lights persisted till the rain stopped on monday.
I rang lexus who confirmed it was a common fault (i didnt mention screen and the moment i said the lights were coming on they imediately asked if id had the screen done.) They recommended i took it back to autoglass.
Took it there today and they 'water tested' it, (which consisted of little squirt from a hose) which revealed no obvious leak, however they have agreed to reseal the the screen next week.
So it will have to be a suck it and see situation.
Im going to start a simple thread to see how many have had this issue and what the outcomes have been.
Dave.