No product on pressing Enter

Hi
Can I ask about a problem that seems to have cropped up between v1.5.15 and v1.5.17? The search still works brilliantly, thank you – unless you hit Enter before the plugin has finished ‘looking’, in which case it returns no results. Give it a moment to find results, though, & they come up as usual under the search box, & can be clicked on as usual. You can see what I mean if you try searching for, say, SKU 6205 on the site. I rolled back to 1.5.15, and hitting Enter straightaway (which is what most users would do) gave the expected part.

I hope you can help with this.
Thanks
Pete

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