Yep I've had the same problem a couple of times regarding tightness in the shank before I worked out what was going on. Conversely I've had a few other times where the tightness has caused the washer to deform under compression and so obstruct the beer flow with the FC fully open, so it's been a bit of a balancing act.
Generally though I'm really happy with the taps, I run shortest possible line length with two or three elbows in each line to avoid the fan in my keezer. No foaming issues other than from warm taps or when I've accidentally over-carbed a keg. Actually now I think of it, one of the taps still had some machining swarf (spelling?) inside which caused a bit of foaming before I pulled the tap apart and knocked it out. From memory I normally run at ~0.8 bar for carb and serve.
Generally though I'm really happy with the taps, I run shortest possible line length with two or three elbows in each line to avoid the fan in my keezer. No foaming issues other than from warm taps or when I've accidentally over-carbed a keg. Actually now I think of it, one of the taps still had some machining swarf (spelling?) inside which caused a bit of foaming before I pulled the tap apart and knocked it out. From memory I normally run at ~0.8 bar for carb and serve.