NPCs are moved outside their wander radius when the player waits
NPCs have a "wander distance". The range that they are allowed to wander about within.
When the player waits or rests, NPCs will be randomly(?) moved around within that radius but should never go beyond it.
However in OpenMW 0.45 and 0.46 nightly (tested on multiple versions including 62b9f1a2), they can end up appearing beyond their set radius when the player waits.
This can lead to them getting onto a different path and ending up where they are not supposed to be.
To better illustrate this, I made this comparison between original engine and OpenMW behavior using the NPC 'Hul' as an example. Her wander radius is 2000. After standing still for a long time observing her, in old engine and OpenMW, she never goes more than a few digits outside that radius. But when using the wait function, things change.
Original engine stays within the radius (albeit with a strange floating bug I think caused by togglecollision) whereas OpenMW she ends up a long way from where she should be.
This mod link (https://www.nexusmods.com/morrowind/mods/47121) explains how I discovered the issue and also gives an example of one instance where it can cause a real problem, but I imagine there could be other problems caused by this too, such as causing directions to be wrong during quests or NPCs ending up somewhere where its hard to reach them.