Elytra can become too expensive in 1.12.2

In 1.12.2 Elytra can become too expensive if repaired with leather, then broken, several times, making them useless if you have yet to add mending, which also becomes impossible. This bug was fixed a few years back, but has cropped back up.

How to Repeat:
Get an Elytra.
Fly until Elytra Breaks.
Repair with Leather
Repeat until Elytra becomes too expensive