So, the error appear when you try to boot an already installed BigSur which with Clover load well? If so with Clover you boot the same partition or you start the BigSur from preboot partition?
I saw the line in the above image (no port micro restart...) during a BigSur install on my hackint0sh too, it is a scheduled restart process, so this is not an issue for sure, however if happens all the time probably the OS does not think the install process has ended, which lead me to think that the install was done through Colver and the install was erroneous, if the install was done through Clover was done using preboot partition to install and boot???
Please give us all details, what BigSur version is there?