Safari 13.0.5 doing premature GET?

I have a PHP script running on a website which logs the number of times access is associated with a key:
http://www.mywebsite.com/admin-query.php?key=8469f8847b8b4d05364ae400d4071d93


If the URL is incomplete and I go to manually alter the URL in the top bar of Safari 13.0.5 (on MacOSX 10.14.6) , when the URL matches what was previously entered, before I even press return, I notice that the script has been run and my access tally associated with that key in MySQL database has been incremented.


To be clear... altering the "admin-query" in the URL to "admin-query1" and then back again without pressing return causes the "Top Hit" and "Google Suggestions" popup to appear, at which point the PHP script is run.


How can that be so?


I've tested with Chrome 81.0.4044.122, and didn't see the same result.