People have claimed that they will actually have the app running and it will say it can't connect. Their phones are not "asleep".
Ah, yes you are correct... there is a THIRD issue, which is - again - just a matter of better communication. When you first take delivery, the delivery specialist will pair your phone(s) app with the car. Then, within a few hours, it will no longer work, because there's some hocus locus that they need to do back at HQ to validate and synch systems. Then, within 24 to 48 hours, it will work again. Several friends of mine took delivery and it was explained to them. My delivery specialist did NOT explain this, and I had to call support to find out. I suspect that many delivery specialists may not sufficiently explain this, leaving owners surprised and irate the next day when their phone key won't work.
So, now 3 documented reasons that I know of for it not to work:
1) Initial setup (temporary issue)
2) Another Tesla up in your Tesla App (easy to change when you know about it)
3) Phone's bluetooth "asleep" (easy to address... just press any button)
All of these can be solved by communication/education - which Tesla needs to do a better job of.
I suspect other issues are user error... until proven otherwise. Software does not just work sometimes and not other times. There is ALWAYS a specific cause.