Mythstone in inventory

Hi, I have been noticing for awhile now once I am done with a level I have not collected as many mythstones as I thought I had picked up so I just counted as I went thru the level. For instance it said I picked up 4 gift and only one in inventory slot a couple endow, only 1 in inventory…anyone else having this problem? I believe it is doing it to crystal also but not as bad.