Disable the search, return home for heroes setting.
Method 2:
Start the building editor and remove all heroes' altars.
Ensure that your strategy does not require any heroes in its search settings.*
Note: Heroes will be deployed if they appear in the troop deployment settings and they are available, even if they're not listed in the search settings as required.
See these issues:
http://forum.brokenbot.org/thread-5961.html https://forum.brokenbot.org/thread-5947-post-51356.html#pid51356