Using a monster spawner to spawn shulkers spawns white shulkers

The bug

When you place a monster spawner and use a shulker spawn egg on it, and let it spawn shulkers, they appear white and the value of their "Color" tag is 0 (white), instead of the expected 16 (for end-city generated shulkers).

How to reproduce

1. Place a monster spawner somewhere in the sky (preferably in the End), for example by flying up high and running

   /setblock ~ ~ ~ spawner
   

2. Then, use a shulker spawn egg on the spawner
3. Wait, and then the shulkers that appear will be white (0) instead of the expected purpur purple (16, default)