Yes, you really have to look carefully.
It's not just a case of sun reflection - the built-in redunancy means that when 1 bulb is dead, one of the others (such as the high-intensity brake bulb) is commandered as a substitute.
So you will normally see lights on - just not the ones that normally should be.
The thermostat heater code in that other thread is a red herring - old codes are stil retrievable by the dealer's GT1 computer even when the SES light has been turned off by a standard code reader.
Sort of like your computer files are not really deleted - just marked as so in the access table.
However, in the present case, it does sound as though there is some odd problem with the light control function.
Could be just moisture, or a bad connection somewhere.
Don't think there is any sort of auto-reset for the bulb warning light - it normally stays on until the bulb in question is replaced.
Might be worth getting a few new bulbs and try replacing them all.