Can't buy Heist Contracts from Vendor

Can't buy some of the Heist contracts offered by Whakano (the ones at the bottom of the page). Can buy all the others.

Had the same issue, restarting the game fixed it for me.
I think the ones that had no price and could not be bought before the restart were the ones with a different currency as price (-> Before the restart every contract was either a chance or had no price, after restart there were ones priced at an alch).