Simple question. Does the Revelation keyword triggers when you discard a weakness card from your deck as part of an encounter card?

No.

Remember that in this type of game, you always follow the wording of the rules exactly with no room for interpretation (unless there's an error on the developer's part that makes this impossible).

From page 18 of the Rules Reference:

Quote

• When an investigator draws an encounter card, that investigator must resolve all "Revelation –" abilities on the card. This occurs before the card enters play, or in the case of a treachery card, before it is placed in the discard pile.
• When a weakness card enters an investigator's hand, that investigator must immediately resolve all revelation abilities on the card as if it were just drawn.

Discarding a card from your deck neither draws it nor causes it to enter your hand, so the Revelation ability is moot.