I have a Lumia 1520.3 and last week iv been to a show so i wanted to recorded my band in 4k but the video stop each 20min with a message like "you have reach the maximum length for this recording" then i need to start it again and again each 20min, btw i have a 64gigs of memory stick and it was only at the half at the end of the show, so i presume the problem is not the space !! WTF ??