How to reproduce

1. Make a datapack with a tag file in a datapack. The file should look like this:

   {
     "values": [
       "#minecraft:invalid"
     ]
   }
   

1. Type /reload in chat
   → The game gives an error message in the game log and aborts reloading the rest of the datapack, Datapacks will show that they're loaded with /datapack list but no advancements/functions/tags/loot tables will be reloaded.