When the culture is changed the NumericTextBox with decimals does not accept valid values when it is rendered inside an editable popup. The issue can be observed when the NumericTextBox is rendered for editing in other components such as Gantt and Grid.
A validation error that the value is not valid appears.
The same behavior occurs in the Gantt component if you try to edit a task, then select Resources and try to edit the Units value - https://dojo.telerik.com/@NeliK/uZepIbId
The value of the NumericTextBox should accept changes when the culture is set.