Flamebreak's explosion particle effects do not appear at all when it gets cast too close to the caster.

It appears that the explosion effects are currently bound to the projectile. So they do not draw when the projectile doesn't appear. The projectile doesn't appear when targeting too close to the caster.

However, the additional visual effect added by the Talent, which increases the aoe, does appear regardless of the projectile. So that effect is not bound to the projectile and appears where the explosion is supposed to be.