> 2. Is there a way to get from Microchip an official clarification for this

It's already clarified in the spec sheet.

Non destruction is guaranteed up to the specified limit.
Correct operation is not guaranteed when you exceed the voltages specified
for normal operation (which are lower than the point where significant
internal diode conduction occurs). (About 0.3 volt outside supply rail
AFAIR.


        RM

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