According to your screenshot, the backup „did not stop“ and has successfully finished.
There was just a warning message that your disk layout has changed. Which will lead to a reset of changed block tracking information.
When such resets happens, the backup job has to re-read all data blocks to make sure that you have a consistent backup.
This can happen when you resize your disks or sometimes when you update your windows operating operating system to a newer minor/major version.
Next backup session will again use changed block tracking.