> 1. If I touch (with my bare finger) to the cap that is connected to the
RB7
> pin of the pic (where the xtal's one pin is connected) the unit does not
> wake up

Consider this, from The Simpsons -

Ralph Wiggum - "The doctor said I wouldn't get so many nose-bleeds
if I kept my finger out of there"

> 2. If I "breathe" on the same cap above.

Hmm, I don't know if capacitors can register disgust. Perhaps it doesn't
like the look of your tonsils. Do you trim your nose hairs ?

> I have put this board to a test in a fridge with -16 deg C and +85 deg C
> (+/- 5 deg C).  And the board still works.  Also, this behaviour has been
> observed with many of the same boards and many of different kind of
> board.

The probem is the water vapour in your breath

> Is this a humidity problem?  Would this problem occur again after it rains
> on the unit (in IP68 box) and then there is sun right after the rain?

Possible, but unlikely. A conformal coating would prevent humidity
affecting the circuit. You could do it yourself with a can of polyurethane.
Then you can huff on it till the cows come home or you fall over

You should also check that someone's fingers haven't been trapped
in the box to avoid problem 1

You could ground the case of the crystal. Be quick and careful, particularly
with the small cylindrical 32k types, or tie it down with a loop of grounded
bare wire. In a sealed box though this shouldn't be necessary

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