I got a Kobo Libra H2O for Christmas, along with an aqua-coloured SleepCover. However if I fold the cover around to the back so that it is completely touching the back of the eReader, it goes into sleep mode. If I fold it into the origami shape to use as a stand, it does the same thing. It is very annoying as it means the only way I can read without it going to sleep is if I leave the SleepCover loose and flapping about.

It's only supposed to go into sleep mode if I actually close the SleepCover, so maybe it is too sensitive and thinks I have closed it. Is there any way I can fix this? If it is some sort of defect, is it the Kobo Libra or the SleepCover that is the problem?