When you summon a mob with a colored name tag, in my case an armor stand, it doesn't appear. It did in the last snapshot and with the exact same code it doesn't anymore.

Here's the code I used.

/summon armor_stand ~ ~ ~ {Invisible:1b,Invulnerable:1b,PersistenceRequired:1b,NoBasePlate:1b,NoGravity:1b,CustomName:"

",CustomNameVisible:1b}