I just used %_folderpath%\%album%.m3u8 in 3.16e 64-bit
with the ticked option to show a confirmation dialogue for the filenames and then pressed
Shift-Ctrl-P
and got 3 confirmation dialogues and 3 separate playlists ...
Which means: I cannot reproduce it.
So: did you follow the additional notes when you installed the 64-bit-version?