Mac OS misrepresenting Library file sizes?

Latest Mac OS and latest FCP. Just got a Samsung 980 Pro NVMe SSD with an Acasis enclosure and it works great. I have a Library on it that currently takes up 125-ish GB. However Finder reports it as 1.35GB which was the size of the Library before I copied a bunch of video files into it. Get Info on the Library says the same thing, but Get Info on the drive itself reveals the true 125GB size (it's the only thing on the drive). However remaining space says 1.87GB remaining which seems more accurate. Dragging the Library to a different drive confirms it's 125GB as that's what the copy window with the bar says.

Is Mac OS Monterey just dumb?

EDIT: Unplugging and replugging the drive fixed it. Not sure why the error in the first place, though.

FYI, I've run into seemingly conflicting sizes for items on APFS-formatted devices. Because of how the OS, APFS containers, snapshots, etc. on APFS devices work, sizes can change over time. Eventually, sizes should become consistent across all ways of checking. Disconnecting and reconnecting devices, as you saw, can force a "refresh" in reporting sizes.

I just helped a friend to move his home folder hierarchy from his internal disk to an external one. After moving all of the files, deleting a bunch of stuff, and re-configuring the OS to use his new home location, the disk usage used varied, depending on how you looked at things. And, we could actually see sizes change in realtime.

So, yeah, it can be confusing and frustrating, at times.

Cheers.