Same here, running PHP 7.3 atm (tested 7.2 as well without any difference) and have disabled the "use GD library" in Studio.  The server is idling but one page load takes 20 seconds cause I have like 91 requests with 404, trying to reach image_transcoder.php

Edit adding: when I call the url directly in browser like

https://una.tld.com/image_transcoder.php?o=bx_events_avatar&h=245&dpx=1&t=1560898952

it works. But in "normal" page call not at all.