in 15w43c fireballs(a.k.a fire charges) shot by dispensers become dragon firebals instead of blaze fireballs

i was playing minecraft and i put down few dispensers and filled them with normal fireballs and expected them to set fire once i shot.
instead it ended up shooting dragon fireballs and made the dragon fire purplish effect .
Steps to Reproduce:
1. place down a dispenser
2. put in fire charge(s)
3. activate the dispenser
(and you get the bug)