Well, market cap of AMP is still considerably lower. To me it doesn't seem too surprising that the less developed platform is being whipped around with trading volume.

A user who I follow on here actually posted something going on with AMPs right now: https://steemit.com/investing/@albensilverberg/synereo-amps-temporary-arbitrage-opportunities

The cliffs of it is they're offering a fixed price on AMP that's a bit lower than what the market seemed to be pricing it at. So for a couple weeks there's an opportunity to sell any time the price gets too high (and you know you can buy from their fundraiser for a better price). So there is probably a lot of trading based on this "artificial dynamic" or whatever being in play.