I used TM since 2015 thru various iterations of OS X and macOS up to 10.15.2, with no problems. Periodically I would check the TM backups could restore, which they always did successfully, until today.
During today's routine TM backup-restore check under 10.15.3, I ran into problems.
Today's backup proceeded normally to completion. The restore under internet recovery proceeded to a "Successful restore" message after which the MacBook Pro rebooted automatically. During the reboot the Apple logo and progress bar appeared on the MBP's screen. When the progress bar reached 50%, the MBP shut down. I restarted the MBP and used the "Option" key, to select the newly restored boot drive. During boot, when the progress bar reached 50%, the MBP shut down. This backup-restore routine was tried a few times to (wired) NAS, local SSD and second MBP, with the same failures.
I have an archived bootable version of 10.14.6 with which I tried the same backup-restore routine. It was successful to and from NAS and local SSD.
Which now begs the question: is Time Machine broken after the Catalina 10.15.3 update?