Why does my Nexus 5 phone keeps shutting down when I use Facebook?

[AC Question]

Hello, I have Nexus 5 running with Android 4.4 version . I have downloaded the latest version of Facebook app from Google Play and it keeps crashing and shutting off my phone after few seconds. How can I solve this problem? I can not update my Android since I will have problems with IMEI code. (Orginal IMEI code was changed.)