Problems with 16" MBP - Big Sur 11.3 beta - kernel panic

Running 11.3 beta 8.
System hangs on shutdown (usually takes 4.5/5 minutes)
This has been happening for a while (at least since Big Sur 11.1).
Booted to recovery and ran first aid on all partitions.
Only received errors on Macintosh HD - Data:

Code Block 
Running First Aid on “Macintosh HD - Data” (disk2s2)
Repairing file system.
Volume was successfully unmounted.
Performing fsck_apfs -y -x /dev/rdisk2s2
Checking the container superblock.
Checking the EFI jumpstart record.
Checking the space manager.
Checking the space manager free queue trees.
warning: Unable to read apfs keylocker ranges: No such file or directory
Checking the object map.
Checking volume.
Checking the APFS volume superblock.
Checking the object map.
Checking the snapshot metadata tree.
Checking the snapshot metadata.
Checking the extent ref tree.
Checking the fsroot tree.
warning: Cross Check : Mismatch between extentref entry reference count (1) and calculated fsroot entry reference count (0) for extent (18406479 + 13)
warning: Cross Check : Mismatch between extentref entry reference count (1) and calculated fsroot entry reference count (0) for extent (95055863 + 216)
warning: Cross Check : Mismatch between extentref entry reference count (1) and calculated fsroot entry reference count (0) for extent (95058867 + 883)
Verifying allocated space.
Performing deferred repairs.
The volume /dev/rdisk2s2 appears to be OK.
File system check exit code is 0.
Restoring the original state found as mounted.
Operation successful.

1) "Unable to read apfs keylocker ranges". Is this a problem?
2) Are the cross check mismatch errors something that can be 'fixed' with first aid? I've booted to recovery mode, ran first aid 3 times, errors persist.

I have Apple Care (and backups). Wanting to know if this indicates I should replace my internal HD?

Thank you.