For example, when the OverflowMode of a Toolbar is set to ToolBarOverflowMode.None/Scroll, changing a tool’s parameters programmatically can cause overflowed tools to disappear.

Reproduction example: https://blazorrepl.telerik.com/mzYKQEYM23bGXmvN56

In the meantime, a possible alternative is to use Adaptive="false" instead OverflowMode="ToolBarOverflowMode.None"