Agreed. If the floppies consistently work fine in some drives but not at all in others, I would strongly suspect a head alignment problem. Tracks are laid down as a narrow concentric rings on the floppy media. If one drive is adjusted differently from another, the ring where the track data is written could end up looking like the space between rings on another drive, so it reads jibberish.

I've never attempted to re-align a floppy head, and I suspect it's not easy. Might be easier to replace the floppy drive.