I'm just trying to gauge how much of a problem it will be to install the replacement. If it'* the short one (20" or so) that goes between the sending unit and filter, it will be easy to replace.
I was actually surprised at how good of a connection the quick disconnects made when I first farted around with them. Rust and debris can prevent a good connection but I wouldn't think that this would be a developing problem. Rather, it could be a problem if it was disconnected recently and made a poor connection upon reconnect.
I'm a pretty thrifty dude so if it were me, I'd buy both the line and a replacement QD clip. I'd first try the clip and if it works return the line for a refund. If not, install the line. Be sure to clean the steel end if you suspect of see rust or other contaminants.