Featured Image Resizing

I run a food blog and usually upload large images. On my blog homepage, I want images to be a specific size 800px X 395px. I had updated this in the customizer options for featured images and everything was working fine until I upgraded to the latest version.
Now, the images have gone to weird sizes. On checking I find that it is picking the minimum resizable size, either the width or, the height and the values that I enter in the Customizer are not being considered. So the image is not being cropped to the size I need.

I checked the forum and found an answer where you had asked to install a plugin and check for any pending CRON jobs. But there is no pending CRON job saying "image_processing_queue".

Please help