I went to my resource pack menu, chose a resource pack, then removed it because I wanted to see the new the 1.14 textures. But when I hit done, it reloaded the default resource pack. I believe this is because minecraft didn't reset the "resource pack changed" variable.
Linked issues
Comments 3
Forward-resolved towards MC-147990, that bug report is more detailed and includes more information.
Can confirm in 20w51a.