I can upload this image if I don't have the thumbnail selected along with the resize. I don't believe it has anything to do with the image itself. It's a .jpg and uploads fine. Only the thumbnail does not get created. Did you watch the video I linked to? This would show it more clearly.
Attached is the image I used. Again, it works fine, just not with thumbnail checked. The error shows but the image is uploaded, no thumbnail is created.
I just tried an image I used in last month's news article and the same thing happened. I was using the RC version last time or 2.7 for years and had no issues. So whatever changed in the final version is what is causing this. I have not changed anything in the settings, etc. The site is hosted on SiteGround.
The PHP IMagick setting is on in JCE. I don't see PHP IMagick in my PHP settings in System Information > PHP Version 7.1.33. Would it show up in there if it was enabled?