The search around text tracks has a spyglass icon to invoke the search function on the keyword supplied in the search text input. It should also perform the same action when Enter is pressed on the keyboard but instead, it rewinds the video selected for preview and plays it from the start.
This issue was fixed with Telescope Executive 2020.1. It is recommended to upgrade to this or a later version. If your TeleScope installation has customizations or you're an OnDemand customer, please contact your Account Manager or support for further assistance with upgrading.
Once upgraded, pressing Enter should search just as it works in the rest of the Telescope application.