That has never happened to me. What changes did you make to the original settings in the aroma installer? If you did make any changes, reflash the kernel and use the default settings.
I've been experiencing random shutdowns with my Nexus 5, they only occur when not connected to the charger. I installed ElementalX along with LineageOS 14.1, running Android 7.1.2. Everything runs smoothly and the random shutdowns definitely seem to have reduced in frequency, however they still happen from time to time.
Are there any settings in the ElementalX kernel that I should try changing in order to resolve the random shutdowns? Thanks