The loading bar for blocks is not smooth

[AtheistAKASaneBrain]

I have noticed that the green bar that shows "X days behind" isn't smooth. When it's near finishing, it goes from "X days behind" to completed all of a sudden. Like for example, right now im 6 days behind, and the bar is not moving, but im sure that im going to go from 6 to fully synced once it's finished. Why is this happening?

[achow101]

It probably has something to do with incrementing that last little bit. It most likely moves at fixed increments and if the last 6 days of blocks is within that fixed increment, it will just not do it to the end since the next increment finishes the whole syncing process. It should however still count down from 6 to several hours before disappearing.

[tl121]

I have noticed that the green bar that shows "X days behind" isn't smooth. When it's near finishing, it goes from "X days behind" to completed all of a sudden. Like for example, right now im 6 days behind, and the bar is not moving, but im sure that im going to go from 6 to fully synced once it's finished. Why is this happening?

It probably has to do with thread scheduling in the client.  The bitcoin application is using lots of computing resources attempting to catch up as quickly as possibly and doesn't always pay attention to updating (cosmetic) display features.  This may vary from machine to machine, O/S, etc.. so the developers may not notice this problem on their machines.