Due to the font changes between 1.13 and 1.14, resource packs for 1.13 that contain new fonts are now incompatible with 1.14. For example, "accented.png" and "nonlatin_european.png" have all the characters rearranged.
Included are these files: the "accented.png" and "nonlatin_european.png" in their 1.13 format, and the same ones in their 1.14 format (as of 1.14.2 Pre-Release 2).
To fix the issue, the two files in question could simply be renamed into, for example, "accented2.png" and "nonlatin_european2.png" for 1.14.2, so that a theoretical resource pack could include both the "old" and the "new" files at the same time.
The pack format has now been incremented in 1.15, addressing this