summon PrimedTnt {ExplosionRadius:x} sometimes works

/summon PrimedTnt

{ExplosionRadius:x}

doesn't work with execute and player commands.

When /summon PrimedTnt

{ExplosionRadius:x}

is used by the execute or by a player it ignores the ExplosionRadius and only works with a command block.

Steps to Reproduce:
1. Type "/summon PrimedTnt

{ExplosionRadius:0}

" as a player or incorporate it into an execute command. It will ignore the explosion radius.

2.Then, type "/summon PrimedTnt

{ExplosionRadius:0}

" into a command block and it will do what