First I want to say sorry if someone had made this already but I tried to search and I havent seen one of this.
Details:
If a creeper explodes on a carpet it wouldn't count the ExplosionRadius it had, apparently it will ignore it and only take 1 heart of the player.
Example:
I was trying to make a race map where you need to be fast enough to skip a creeper that was going to explode, I made the creeper with 127 ExplosionRadius and he was already ignited with 10 of fuse (thats part of the race), but I was noticing that the creeper was only taking me 1 heart or sometimes just a piece, after alots of try I changed the ExplosionRadius to see if I was getting to negative numbers has result and it was the same, until I removed the carpet and the explolsion was exactly 127.
Extras:
I could make a video if its necessary.
Thank you for your report.
However, your ticket has been resolved as a duplicate.
This issue has been linked to the original bugreport: MC-145. You can find or add further information on that report.
Please search before reporting any bugs, as it's likely that one exists already.