How to stop Central Admin People Picker from showing results for both trusted identity provider and its associated claim provider

I have a trusted identity provider which is associated with a claims provider.

Get-SPTrustedIdentityTokenIssuershows that ClaimProviderName is set to match the custom claims provider.

This appears to be sufficient to give the expected search results when using the claims picker under e.g. site -> People and Groups -> Site Members as follows:

However, if I access the people picker under Central Administration (e.g. when managing administrators for a Secure Store target application), I get a different picker, which includes both of the expected results, but additionally shows spurious results for whatever happens to be typed in under the trusted identity provider:

These entries are correct:

However, this entry is incorrect - there is no "vogon" user, and the trusted identity provider shouldn't even be showing results directly, since it is associated with a claims provider:

How do I get the People Picker in Central Admin to honor the ClaimsProvider association for a trusted identity provider?