Per Moesh's comment on MC-46956, I'm making a new report for this.

Entity explosions harm teammates, when friendly fire is false

Steps to reproduce:

1. /team add TestTeam
2. /team modify TestTeam friendlyFire false
3. /team join TestTeam
4. /summon creeper ~ ~ ~ {Team:TestTeam,Fuse:0s}
5. notice how you take damage from the explosion

Affected entities:

• Creeper
• Wither
• End Crystal
• TNT
• Minecraft with TNT

Expected result:
Friendly fire is respected and their explosions cannot hurt teammates.