Tested this with OC v3.3.14, I couldn’t reproduce it, however, did notice that the images were inserted in reverse order. Yours appear to be inserting in random order.
Is there a trick to this? I am inserting images using the Rich Editor with Media Manager.
No trick, just standard select from media manager and insert. I’ve tested it in different scenarios, my own plugin, and the pages plugins, different browsers and projects selecting the same images here are the outcomes: