Token seeing through wall occluder

[Ecks]

I ran into a situation where a player token and NPC token were both able to view through a wall occluder. I'm able to recreate in a new 5e campaign with no extensions.

To recreate:

1. Create a new 5e campaign
2. Load Waterdeep: Dragon Heist and Zacchaeus' Dragon Heist Map Pack
3. Open Xanathar-Guild-Hideout from Zacchaeus' Dragon Heist Map Pack
4. Add a Drow NPC to the Combat Tracker (Note: NPC has Darkvision)
5. Drop the Drow NPC onto the map as shown here: Occluder3.JPG
6. Enable Player Vision Preview. Line of Sight and Lighting should already be enabled
7. Drag the Drow NPC token side to side (using mouse) as shown by the pointers in Occluder3.JPG until it is able to view through the wall occluder. Occluder2.JPG shows the occluder definitions
8. Possibly related: If I disconnect the "toggleable wall" occluders that are attached here (bottom left point in the blue square in Occluder4.JPG), the token can no longer see through the wall occluder (with the token moving back and forth). If I reconnect the points, then I can recreate again by moving the token east-west repeatedly as before

Note, it's also possible to re-create using a separate client instance over localhost with a PC that has darkvision or with a PC with no darkvision and a light source. So it isn't limited to just "Player Vision Preview" mode.

FGU v4.1.0 (2021-05-12)
5E ruleset v2021-05-11
Windows 10

[Zacchaeus]

Yes I can recreate and it does seem to be related to the toggleable wall, If I redraw the wall and insert an additional point before the junction then it doesn't happen.