Does Ravenbloom get +1 for each instance when you repeat it, and what happens if you repeat and complete the effect twice but the opponent defies it on the 3rd attempt?

Ruling: Repeat adds additional effects to a spell rather than playing a whole new one, so it's only one instance on the chain. You can only repeat once.

Nuances:

• The complete rules for repeat interactions are not yet available in the current ruleset, so some edge cases remain unclear until updated rules are released.