I am surprised if they are accepting deposits from Revolut. Knowing how Kraken is very strict from which banks deposits are made and not accepting deposits from some (traditional) banks, I would not be surprised if they stop deposits from Revolut in some months. Especially if they face frauds at a high rate.
You shouldn't be surprised at all.
I cant understand why the sepa transfers wouldn't work from revolut to kraken.
Continuing to block the money flow, would be a joke.
There are KYC for both kraken and revolut, so frauds are limited if not eliminated.