Trying to summon a creeper with PersistanceRequired:1 within spawn region (while there are no players within spawn region) will fail, however summoning sheep, or item entities will function.
MC-46897
Cannot summon hostile mobs in areas not loaded by players
Resolved
Incomplete
1
Is this still a concern in the current Minecraft version? If so, please update the affected versions in order to best aid Mojang ensuring bugs are still valid in the latest releases/pre-releases. If this has been done, we can reopen the issue.
Keep in mind that the "Resolved"-Status on this ticket just means "Answered", and that we are waiting for further information on whether this issue still exists or not. We will reopen it as soon as the requested information has been delivered.