When using MarketPress with Redis Object cache the checkout page returns old results. We have tried this on two different servers and got the same result. We first thought it was related to product variations but after further testing we realized it was all products that where returning the wrong result (wrong product and price)on the check page. So far we are only getting errors with the marketpress plugin and so far only on the checkout page.
We are using azure redis with the till kruss ( https://wordpress.org/plugins/redis-cache/ )