Potplayer 'Angel Script' causing odd problems

[seaberry]

I don't know if I'm allowed to name the file that's causing this problem, so I've blacked it out in the title bar.

It's an episode of a new 6-part series and it opens on my computer, as do all video files, in Potplayer. (1.7.17508)

But this file (and all the rest of the 6 episodes) causes Potplayer to display, on startup, the command box shown in the attached image. If this box is 'x-d' shut, it and Potplayer both close. The player only remains open if the box is minimized. But most oddly, all of the subtitles are duplicated on two separate lines, one above the other, like this: (but single spaced)

'What are you doing?'

'What are you doing?'

The subtitles are also doubled-up in Potplayer's Subtitle Browser, but they're subsequent, ie, What are you doing?\What are you doing?

Comments, please.