The reason behind this behavior is that at this stage, Telerik REPL can install only one instance of dll with a specific name and in case the package includes another one with identical name it throws an error.
In this specific case the issue is not directly associated with the IcuBlazor package itself but with another package it is dependent on - FSharp.Core. Although it is not a commonly used practice, it looks like this package contains multiple dll-s named FSharp.Core.resources.dll for localization purposes (can be found in the different languages folders). This eventually causes the error due to the above listed configuration of the REPL.
Thank you for noticing and reporting this behavior! We've additionally logged it internally for research and revision. The public bug report is associated with the internal one and thus you can easily track its status.
Last but not least, as a small token of appreciation, I've added some Telerik points to your account.