If you want to use yay for the -git packages, you should probably run yay --gendb once.
That makes sure the yay db is up-to-date with what is installed…
Because it might think that some -git packages are out of date (if they have been updated with some other package manager in-between)
Just did that. still nine upgradeable packages.
I guess this solves yay and pamac CLI giving conflicting results then? I’m still not sure if pamac GUI stalling is a bug or a problem on my side 
Just not implemented very well.
Again, if you disable the “check for development updates” (or whatever it’s called in the pamac settings) it should not get stuck… (actually it does not really get stuck, just wait 10 minutes or so, it will complete eventually).
However, if you do that, you will not receive -git package updates with pamac. If that is ok for you, so be it. If not, you might want to switch to yay (at least for the -git / devel packages).
Another question you should probably ask yourself: Do I really need the -git version of those packages at all…
edit
Actually there is an issue report about this as well:
Wow…that is an old bug.
Also now I’m curious as to why pamac GUI, pamac cli and yay seem to disagree with everything.
Even though Pamac is a fine AUR helper - remind you that AUR is unsupported - therefor disable all your AUR update searches.
If you really need to be up-front with AUR script updates - please create an account on AUR and signup for notification when your favorite script is updated.
While Pamac has the option - AUR is for Arch Linux and therefore unsupported on Manjaro.