Steps to Reproduce

1. Create new "Creative" world with "TNT Explodes" option turned OFF
2. Place one block of Bedrock in a 1x1 hole
3. Surround the Bedrock with TNT (so it is one block above the bedrock)
4. Place an End Crystal on top of the Bedrock
5. Use Flint and Steel to light the End Crystal

Observed Result
The TNT explodes

Expected Results
The TNT is not affected by the End Crystal explosion

Note
If the Bedrock is at the same level as the TNT, then the TNT does not explode.