Given I just watched all 3 seasons in the last 2 weeks, I never got a feeling that 2-3 years had transpired. The only thing that explicitly would have suggested any significant periods of time had lapsed was the fact that Piron BoD had given Alec "2 Months" to get HALO launched - and that happened in the span of a few episodes. Otherwise, it always felt that it was only a few days transpiring between episodes.
Then again, maybe it's just me, since I did watch them all in the last 2 weeks. However, with no 'seasons' (ie, change in weather), and no clear indication that 5-6 months transpired since the last episode, or in between the Seasons (of the show), that's what's throwing me off.
Nah... it's not just me. Season 2 immediately flowed into Season 3, which immediately flowed into Season 4. Even if TV time and real time are the same, it's 13 weeks per Season, we've still only transpired about 1/2 a year Since Kagame blew himself up on is birthday. There may have been a bit of a gap between Season 1 and 2, but it sure didn't feel like it was over a year that had lapsed - and that kid was approaching the age of 2.
I think this is one of those 'kids aging fast' scenario's that TV shows just expect viewers to accept - but I don't think it was necessary.