today's update puzzle

[Juan R. de Silva]

I have multiboot set up on my laptop. The main system is Ubuntu 14.04 
upgraded from Ubuntu 12.04. Nothing wrong with it. On another partition I 
have Ubuntu 14.04 fresh install. Both systems essentially configured the 
same way. I mean the same repositories list and nvidia drivers mainly.

This morning, while running my main system I was prompted for upgrade and 
happily accepted it. The upgrade broke the system, which happened to me 
at the first time since I started ever using Ubuntu (starting from Feisty 
back in 2007). I could boot into tty but Unity did not start. Well, I was 
pretty surprised and a little pissed off, since I'm running an LTS 
release and surely did not expect this to happen.

Luckily it did not take me long to find the reason and to fix it. My 
kernel was upgraded form v. 3.13.0-24 to v. 3.13.0-27. But for some weird 
reason the upgrade did not installed the headers for new linux image. 
Thus the new kernel was left not configured. I installed the new headers 
and reinstalled the kernel. The system was up and running in 10 minutes.

About 5-6 hours later I switched to my another system - Ubuntu 14.04 
fresh install. I checked for updates and found that no kernel upgrade was 
offered at this time. I made upgrade and checked for updates again. No 
new kernel offered.

Now I have 2 identical Ubuntu 14.04 running different kernels - one is 
using v. 3.13.0-27 kernel and another one is still on v. 3.13.0-24 kernel.

Should I worry about where the kernel v. 3.13.0-27 came from in the 
morning or this is Ubuntu folks just caught up a bug in the new kernel 
upgrade?