We don't know. Maybe they wanted to try to product test Ethereum wallet working, maybe not. We just have to see what will happen. I don't believe it is a scam.
Why test with 180,000 ETH instead of 1 ETH? I smell a rat and so do lots of others. Kraken have just announced that they are coming back online shortly. I'm waiting for other announcements saying that there's yet another delay and a final one saying that funds have been lost.
Nobody in their right mind will ever trust Kraken again, they are finished!