We can't reproduce your problem. With a clean joomla and JEM, with only the official templates and plugins, this works best. So there must be an interference between your composition and joomla, which causes this. You don't give any informarions, so you don't get help!
Testing JEM 2.3.0 beta3 local on clean latest Joomla (3.9.11) Protostar php7.3.8 (no mails)