I have a Brother label printer P-touch (PT-P300BT) model.
It cannot print shrink tube tapes.
The holes in the tape cartridge contain the tape information, which can be analyzed to trick the machine into printing.
The third image is what I figured out over the course of a weekend.
The blank spaces are not supported by the P-touch printer, so the code is either unreadable or there is no data at all.
The Brother label printer prints on the opposite side of the transparent film, so it produces a mirrored image.
However, if you set it to 12mm wide fabric or ribbon tape, it will print a normal image.
If you punch a hole in the tape cartridge or cover it with tape, set it to ribbon tape, and reduce the font size slightly, you can print on shrink tubes without any problems.