Using /locate structure stronghold only finds strongholds near spawn

Steps to reproduce:

1. Create a new world
2. Turn on cheats
3. Teleport 1000000 blocks from spawn in any location 
4. Use /locate structure stronghold to locate the nearest stronghold. 

Expected results - a stronghold will be located within 10,000 blocks of the player's current position. 

Actual results - the only strongholds located are within a few thousand blocks from spawn.