Credits are not shown when leaving end for the first time but after that are always shown

The bug

Credits only appear when you have left the end at least one time respectively when the seenCredits tag of a player is already true (1b).

How to reproduce

1. Create a new world
2. Go to the end
3. Beat the dragon for the first time
4. Go through the portal back to the Overworld
   → The credits are not shown
5. Go to the end again
6. Go through the portal back to the Overworld
   → Now the credits are shown

Code analysis

Based on a decompiled version of 17w13a

It looks like the values for the SPacketChangeGameState packet (deobfuscated name: id) are just interchanged when the method EntityPlayerMP.changeDimension(int) (deobfuscated name: nn.b(int)) creates it. It should use 1.0f when the player has not seen the credits yet.