Hi, yeah this problem has been going on for a quite a bit now, shortly after the last update that was downloaded. I deleted the update and downloaded it again as well as the app but after a few watched videos it will continue to do this.
I did test this a few more times and it does seem that the number of videos you can watch before this bug occurs does vary after watching at least 2 1 documentaries on the third I wasn't able to use the controller. The other times I tested it it started doing it after the 3rd or 4th video though again this varies and often will start occurring after the first video. Hope this helps.