Okay, do you see any error messages within the error log? Do you still return 200 results at once? If so, then that could cause the issue, as the script may try to resize all of them one by one and that could probably cause a memory limit issue and halt the process automatically.
Can you please also check the image source sizes for the featured images here: https://i.imgur.com/1I3AHsD.png
You may have different options, try choosing the smallest possible dimension. That alone could resolve the problem without having the cropping feature enabled.
