Could have been low pressure at the spigot. I bought a $12 screw on pressure gauge from Home Depot so I can check the incoming pressure as I connect. Under 60psi, I don't bother with the regulator to maximize flow.
Next time this happens turn off the spigot outside, turn on your on board pump and see if the situation improves. If it does, it's the incoming pressure. If not, possibly your filter, or maybe there's something else going on.
Now-2014 Sierra 346RETS 5er BUB
Then-2002 Keystone Springdale 286RLDS TT
Nights camped in 2014-28, 2015-127, 2016-10