(We've had a similar issue before relating to caching here, iirc).
When you go to search, the first search you make will return no results. From that point on, search will work. Here's an example of me searching for "korg" - the first time I hit search I get no results, if I then search again, I get results.
This seems to be Safari (Mac) only - I don't think it happens in Chrome, for example, and also seems Ok on Safari iOS when I tried just now.

Something to add to the list for the web team to look at, I guess...