All was going well until I opened the keggle valve. No flow! Tried blowing through but that didn't help nor did giving the wort a good stir. With no other option, I sprayed my arm with StarSan and dunked it in. I could feel what I believe to be hop seeds clogging the hacksaw slits of the manifold (on the underside) and, when I moved them, the flow began. Stopped moving my fingers and the flow stopped. So up to my arm pit for like 20 minutes.
Looks like I'll be ditching this:

and getting a SS braid from Morebeer. Would I have better luck?
Hops in the 15 gal brew were:
First Wort Hopping: 4 oz Galena
When brew started boiling: 4 oz Cluster
After 50 min boil: 4 oz Columbus and 4 oz Cascade
After 60 min boil: Flameout
These were all leaf hops.
I usually use Cascade and I've never used the others before. Never had a problem before this.
Any ideas?
Cheers!