From the description of the Zone of Truth spell (PHB, p. 289):
Until the spell ends, a creature that enters the spell's area for the first time on a turn or starts its turn there must make a Charisma saving throw. On a failed save, a creature can't speak a deliberate lie while in the radius. You know whether each creature succeeds or fails on its saving throw.
If you read this carefully, you will discover that a creature staying inside the area has to roll saves every turn until it fails one. After that, it is affected until the spell ends or the creature leaves the area. However:
- The last sentence is about a singular save.
- This is the only spell that works like this, but it is not explicitly stated.
These led me to question whether this is intentional or not. Can anyone point me to Sage Advice, official clarification of the designers' intent, or errata that addresses this?