If its using cm11 there was a bug where app icons would disappear from the launcher after app updates.
Apps uninstalling themselves though... Besides user error or bad judgement I can think of many possible scenarios where apps could be removed/disappear.
I wonder too if google's new app checker service improvement could remove them if it didn't like them. Perhaps even being triggered during an automatic update.
[Ah yes, there is what I was looking for: "Google Play scans apps that are uploaded for malware. If an app is later discovered to be malicious, Google can automatically remove it from the devices it’s been installed on." -> http://www.makeuseof.com/tag/cracked...e-downloading/
And that is only one way it can happen.]
HTC sensation 4G | cm11 albinoman ROM - 3/2/14 Workaround for incoming phone calls going to missed (including the swipe issue) with all cm based roms -> http://forum.xda-developers.com/show...&postcount=884
(Longest recorded uptime: 1,060 hours)
Nook HD+ 32 | cm11 emmc official ROM (Longest recorded uptime: 331 hours with much daily use)
....Nook HD+ 16 | (Returned due to random reboots; defective tablet)