Does Blue Sentinel's passive ability cause its own "When I hold" triggered ability to trigger an additional time?

Ruling: Yes. Blue Sentinel's passive ability states "Your hold effects for holding here trigger an additional time." Since the card text does not specify "other" hold effects, it applies to the Sentinel's own "When I hold, [Add] [A] at the start of your next Main Phase" ability. When you hold the battlefield with Blue Sentinel, you will add 2 Power total at the start of your next Main Phase.

Nuances:

• The passive ability does not exclude the card's own triggered abilities from its effect.
• This interaction is consistent with how passive ability modifiers apply to triggered abilities in Riftbound.