Second root partion empty after Yocto update from dunfell to kirkstone

Hi, we have been using mender successfully for some time with an RaspberryPi like device and a self made yocto image based on dunfell version.
Now we have updated to Yocto kirkstone and I noticed that in the initial image the second root partition is empty. Under dunfell both root partitions are identically (until the first update via mender). Boot and Data partition are still fine.
Is this a normal, intentional behavior?

Thank you!