Thank you for the repro demo. Indeed, the widget will lose its pre-selected value when it has an initial value (options.value) and model field has a default value too. I logged the case for further investigation and fix. We will try to address the limitation in some of our next official releases.
For now, the best solution is to leave the grid's model to take control over the UI editors:
@(Html.Kendo().MultiSelectFor(m => m.Members)
"Type user's name..."
@Html.ValidationMessageFor(model => model.Members)
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