When I'm using undo/redo feature of bryntum gantt, I face an error sometimes then undo/redo doesn't work anymore.
An error is shown in browser's console.
gantt.module.js?454302:13 Uncaught (in promise) TypeError: Cannot read properties of undefined (reading 'get')
at _0x305c19.equality (gantt.module.js?454302:13)
at EngineTransaction.onQuarkCalculationCompleted (gantt.module.js?454302:13)
at EngineTransaction.calculateTransitionsStackGen (gantt.module.js?454302:13)
at Generator.next (<anonymous>)
at EngineTransaction.calculateTransitions (gantt.module.js?454302:13)
at Generator.next (<anonymous>)
at runGeneratorAsyncWithEffect (gantt.module.js?454302:13)
at gantt.module.js?454302:13
It's reproduced at your demo site.
I think this is a bug of bryntum gantt.
I hope it will be fixed.