What you are seeing is a change in Finder's contextual-menu wording.
With two files copied, Finder displays “Paste 2 Items,” but when you hold Option, macOS 27 displays “Move Item Here” instead of “Move 2 Items Here.”
Finder has previously used the number of items in this menu label, so the change you are seeing is specifically the loss of the item count. (Ask Different)
Apple documents Option-Command-V as the command that moves the files in the Clipboard from their original location to the current location. Mac keyboard shortcuts — Apple Support
If selecting “Move Item Here” moves both files, then the move operation itself is working; the difference is limited to what Finder displays in the menu.
If only one file moves, that would be a separate functional problem.
I could not find Apple documentation explaining why macOS 27 no longer displays the number of items in this particular menu command.
Therefore, it is reasonable to report the changed wording, but there is not enough information to conclude whether Apple intentionally changed it or whether it is a Finder bug.