Wierd starting issue

[tig488]

2014 Sierra AT.  146k miles.  Had engine rebuilt 14 mos ago from lifter failure.   Has been even fine since then.

 

About 6 mos ago it started sporadically not starting.   I’d say once every few weeks I get in and turn it over and it acts like the battery is dead. I get a click but no start.  I try again immediately and it starts.   Once it cranks I get the “theft deterrent system” dash light on the dash and I have to clear it, and the alarm cel goes away after a few cranks.  a few weeks goes by and it does it again.  
 

Battery has been tested and is good.  
 

it has also done it when I try to do remote start.   
 

leaning towards replacing the starter.   
 

any thoughts?