My fault. So PixiJS is version 4.5.4. NWjs is v0.12.3, or whatever RPG Maker MV came with. No other plugins, just the one you left in the demo. RPG Maker MV verions 1.5.2
Viewing post in Turn Based Movement - RPG Maker MV/MZ Plugin comments
All good! Ok, we believe the issue might be tied to the NWjs version. Please try updating to at least v0.24.0 or higher as that's usually what comes with MV nowadays. Would also recommend updating your RPG Maker version to 1.6.3 if possible.
If neither of those updates work, then send your copy of the demo project over to support@myth-atelier.com and one of us will replicate the error in a sandbox using the version info you've given us and then follow up with you on steps for how to get things working on your end :)