P: Keyword autocomplete sometimes fails to find existing keywords

Sometimes, keywords that I know exist don't show up in keyword autocomplete.  I've attached two screenshots. The first shows that a given keyword exists (I created it a week ago). Now I want to apply the same keyword to a larger set, but typeahead doesn't think it exists. These screenshots are taken a few seconds apart. 

Other times, attempting to autocomplete turns up nothing at all. But then later it kicks in and suddenly they're all available. 

Using Lightroom v7.2