Suggestions UI fails with a single core

From a build of master from today (15 Feb 2018), the new Suggestions UI doesn't work well with a single core (meaning, Solr in standalone mode). It shows a cryptic error that doesn't tell the user what's wrong.

• The screen should be hidden if it's not supported in standalone mode.
• In the left menu, the Suggestions item in the list is not highlighted properly to show that's the screen you are on. Whatever screen you were on when you clicked "Suggestions" is highlighted.
• The only error shown to the user is a red bar with "no core retrieved for null", which doesn't explain what's going on.
• Errors are logged and shown in the Logging UI, but it repeats the same "no core retrieved for null" - nothing explains that it's not supported for standalone mode (I only happen to know that).

I've attached a short .gif of the user experience with this - it's rather poor.