Version 0.8.4f
I see there’s a similar report from Mar '21 which is now closed, but the issue remains in 0.8.4f. Minions do not always appear with you when using portals, although they still show as summoned and will sometimes run back on screen from elsewhere if you give them 30 secs or so.
This can be a character-killing issue if you use a town portal and mobs have respawned around the portal while you’ve been in town.