Inline comments are present in the item json files of the vanilla behavior pack. This is a non-standard use of json which breaks 3rd party parsers.

Examples include (bold for clarity):

appleEnchanted.json :

  "duration": 120, // 2 * 60

  "name": "resistance", // damage resistance

golden_apple.json

  "duration": 120, // 2 * 60

pufferfish.json

  "name": "nausea", // confusion

wheat_seeds.json

  *  "crop_result": "wheat" *// wheatCrops

Suggested fix is to remove inline comments where currently present.