I updated to the latest Lightroom (2015.5) and Photoshop CC (2015.1.2) this morning which was a bad idea! My export action on multiple raw files will only open one file at a time in Photoshop!
I've recreated the droplet and tried it again. It doesn't work.
I can export multiple files without export actions and that works.
Help! This is very annoying and slowing down my work!
I can confirm. The droplet now only applies to the very first exported image and doesn't get applied to the rest. Looks like a bug. You should enter a report at feedback.photoshop.com