To be honest I'm not entirely sure about that. The server seems to be fast enough for me.
I've looked at the issue once again, and when it happens, I see the following error message in the console:
Failed to load resource: net::ERR_INCOMPLETE_CHUNKED_ENCODING
This could indicates that at some point the page loading was cut off from loading to the browser. It could be an overload, but I usually see a half-loaded page or a page with an internal server error, but this is very different.
I've googled this error, but there are like 20 different things listed as cause on various forums, so I don't exactly know what is behind it. My guess is that the plugin might try to send the result IDs to the default search page, and the results page is either trying to load all of it at once, or something is happening inbetween. (or something else completely)
If you want, you can provide temporary FTP details, and I will go through the plugin code line-by-line to see if the error is caused somewhere internally. If so, then I might be able to fix it, if not then at least we will know it's not related.Best,
If you like my products, don't forget to rate them on codecanyon :)