yes, a good deal of the issue between Manjaro and Arch is the package update release cycle.
As I understand it (and I could be slightly off on the exact timing here) Arch Unstable is basically: "this new package came out, here try it 'as is' without any testing"... Arch Testing is maybe a week behind that; Arch Stable is another week or two behind that.
Manjaro Unstable is basically Arch Stable (with the added Manjaro stuff)... Manjaro Testing is about a week or two behind that, and Manjaro Stable is another week or two behind that..
So, in the end, if you are on Manjaro Stable, you're likely about 2 to 2 1/2 months behind the actual bare bones untested package release... and somewhere around 1 month behind the Arch Stable version.
That extra testing tends to have a lot of impact.