^{Update by Mega_Spud:}
Summary:
Sometimes cactus cannot be smelted into green dye in a furnace. Looking at the items data, it seems that if the cactus block has a block state age of 1 or higher, then it won't smelt correctly. If the block state age is reset to 0 (by placing and breaking it again) then it can be smelted correctly.

Steps to Reproduce:

1. Place a furnace down, and add fuel
2. Break a cactus block, and place the cactus into a furnace

Observed Results:
Sometimes, the cactus won't be smelted into green dye. Placing and breaking the cactus block again allows it to be smelted correctly however, as the block state age is reset to zero.

Expected Results:
The cactus should always be processed into green dye correctly.

Screenshots/Videos attached: Yes - cactus_smelt_bug.mp4

Notes:

Original Description:
What happened to green dye? There is green everything else. No way to make those things without the dye.

Even in creative mode there is no way to get green dye.

Searched for answers but found nothing, so don't know if this is recent or not?

This is with experimental mode activated.