This has to do (mostly) with the number of content tabs you have currently open. It may also have to do with the number of Panels you have open but I'm not certain about that part. The things that can cause this can vary from computer to computer based on the amount of ram you have, video ram, and how many other applications you currently have open.
to fix that, close some of the Content Panels you currently have open.
Thanks for your feedback.
Bridge imports the files in new content panel if “Open in Bridge” option is selected in Photo Downloader.
Please close some of the content panels and try.
We're happy to announce the release of Adobe Bridge Beta (18.104.22.1686). This update includes the fix for this issue. To see the list of all fixed issues in this Beta release, click here
Please update or install Bridge Beta via the Creative Cloud Desktop app.
Steps to install/update
Install: Go to the Creative Cloud desktop app and select Beta apps in the left sidebar of the Apps panel. Then select install for your beta app.
Update: Go to the Creative Cloud desktop app, click on Update in the left sidebar of the Apps panel and Check for updates. Then click update for your beta app.
Let us know if this Beta release resolves the problem for those affected, and share your feedback.