Not A Bug Dress Down / Harbinger of the Seas --- Bugged Interaction?

[XShockWaveX]

In this match, I have Harbinger of the Seas in play and a Flooded Strand (amongst other non basic lands). I cast Dress Down and it resolves. The Harbinger seemingly loses its ability (ie. the text gets greyed out), but I do not regain the ability to activate my Flooded Strand --- it remains an island, and so do the other non-basic lands in play.

 

[XShockWaveX]

Thanks for clarifying and apologies for the incorrect report.

 

[Torbin]

Tag applied: Not A Bug

This interaction has to do with how Continuous Effects applies in layers of pre-determined priority. The Type changing ability of Harbinger of the Seas is a Layer 4 type changing continuous effect which is higher priority and on a different layer than a layer 6 ability changing effect. So as Dress Down removes a layer 6 continuous effect until end of turn, the layer 4 effect remains unchanged and stays in effects as long as Harbinger of the Seas is on the battlefield or another layer 4 effect is added on that stack of effects.

For more information, please refer to the section 613. Interaction of Continuous Effects in the comprehensive rule book.