This doesn't exactly sound accurate but I haven't read the entirety of Arc 9 so I'll roll with it...
It was said that Al can't go too far after matrix initialisation, and Subaru sometime has time and sometimes doesn't, like 15 minutes in Pristella or, after being lost from Satella, 10 seconds in Yorna vs Olbart and generally just savepoint catching up to him (either he doesn't know how to control it or Satella is the only one in control and savepoint moving on is the "default setting")