As I was finished killed a witch I spawned in with an egg, in a desert biome if that makes a difference, I was unable to break any blocks afterward, it's been three minutes since I believe the witch used a splash potion of weakness on me and i've been unable to destroy any block in creative, I switched back to survival and successfully broke a grass then i switched back into creative and could still not destroy a block,
Difficulty was on hard.
I feel that this is a major issue that should be addressed, thanks for taking the time to read.
PS, I attached a Bandicam file of me switching game modes and destroying a block.
PPS: Upon retesting it, it appears only the sword is incapable of destroying in creative after the witch battle
Edit: The sword did work to break items and blocks before the witch battle.