The diggers backpack isnt picking up some items I have noticed clay, sandstone, grass block and soulsand that i have noticed so far. The version im using is 1.12.2-5.8.2.387

I propose to add the following item stacks to the diggers backpack:
minecraft:clay
minecraft:hardened_clay
minecraft:ice
minecraft:packed_ice
minecraft:snow
minecraft:stained_hardened_clay
tconstruct:slime_dirt
minecraft:clay_ball:0
minecraft:flint:0
minecraft:sandstone
minecraft:snowball:0
minecraft:soul_sand:0

We could add the following ItemStack to the forester backpack:
minecraft:golden_apple
minecraft:chorus_plant
minecraft:chorus_flower
minecraft:chorus_fruit_popped
and related ore dictionaries:
listAllFlowers
plant

Also, we could consider the related tools to be white-listed in their backpack. For the diggers backpack, that would be:
forestry:broken_bronze_shovel:0
forestry:bronze_shovel:0
forestry:kit_shovel:0