Hard-Drive Disconnected While Time Machine Running. What Consequence?

Dear Apple Community:

I have quite a concern. I’d greatly appreciate your input on it.

My regular practice is to use Time Machine to backup, on rotation, to three different hard drives. One of them I keep off-site at all times, and one of them I keep in a fireproof location at the place where I use my Mac. Today, having retrieved my off-site backup for use, I was anticipating a lengthy backup since I haven’t used it in quite a while. After running the backup for roughly 15 minutes, a book on my desk ever-so-slightly jarred the hard-drive’s USB-C cable that was plugged into my MacBook Pro. Unfortunately, I got the horrifying “You didn’t properly eject the disk before unplugging it” message. (My paraphrase.)

Since the Time Machine backup routine was still running when this occurred, I’m concerned what damage might have resulted. I immediately ran Disk Utility’s “First Aid” routine on the backup drive, and fortunately, I got the green checkmark and the words “Operation Successful.”

One of my questions is this: Does the green checkmark mean that both the data and the hard-drive itself are ok? And perhaps just as important: What has become of the data that was backed up during the 15 minutes prior to the mishap? I am hoping that Time Machine will totally DISREGARD all the data that was transferred, knowing that a “not rejected properly” interruption occurred during the backup session.

One clue I have that Time Machine is wisely disregarding that data is this: Time Machine indicates that my “Latest Backup” is another one of my backup disks; NOT the one that had the mishap. That was reassuring, so I then re-ran Time Machine with the hard-drive whose cable got bumped. When I commenced the backup, I received another clue that Time Machine will be disregarding the data that was transferred during the mishap session. When the new backup began, it listed the amount of data needing transfer as 13.33 GB. If I recall correctly, that is the same amount that was being transferred during the mishap backup (but of course, when I ran that backup, I wasn't paying as much attention to the transfer quantity; I just recall it being a large number like 13 GB.)

I hope you won’t mind if I state the obvious, but the reason I’m showing such concern with all these questions is this:  if one day I ever need to use this particular Time Machine backup drive to restore my computer, I want to know if I can confidently rely on its data integrity.

Thank you for any help you can offer me with these questions! :-) Mark