"Failed to retrieve extension data. Server not responding" on Firefox

Steps to reproduce:

1. Click on the "Install" button to install an extension
2. At the same time search for another extension

Expected results: The search works.

Actual results: The search works but, on Firefox a message appear at the bottom of the page "Failed to retrieve extension data. Server not responding". Could reproduce on local instance and on Cloud (11.10.4)

Couldn't reproduce this on Chrome, IE or Edge.