User blog comment:GoosebumpsArt/Say Cheese — and Die Screaming! (Review)/@comment-25506374-20170712020428/@comment-4207976-20170712034504

The reason why The Haunted Mask II wasn't acknowledged was, because it didn't receive a Classic Goosebumps reprint around the same time as Scream of the Haunted Mask. That's just me speculating, but it makes sense.