Promaster ETTL cord issues

I have this Promaster ETTL cable

http://www.amazon.com …Canon-Flash/dp/B00092GL3O

I noticed that every once in a while I will make the 580EX II switch from ETTL and the it will only show TTL. I scrolled trough the menu options and ETTL is no longer available (it shows TTL instead). If I connect the 580 directly to my XTI ETTL shows up. I also noticed that sometimes if I disconnect and reconnect the cable then ETTL shows up again.

I guess this would indicate a loose connection but I've checked the cable conecction several times.

This happened twice. The cable is new (got it last week).
Happened with my XTI+580EXII+Sigma 20 1.8

Has anyone experienced anything like this?

Curtis, I heard you use a similar Promaster cable. Have you had any issues with yours?

It sounds like a loose connection somewhere.

My Promaster cord seems to work fine with my 580EX II.

I heard someone say (maybe even you Curtis) that if you the mount has a screw lock it can pull the pins away and cause a bad connection...

lmulderi wrote in post #5378556
I heard someone say (maybe even you Curtis) that if you the mount has a screw lock it can pull the pins away and cause a bad connection...

Interesting.

Can you tell me more on this?

Are we talking about the connection on the flash or the one on the camera?

Thanks.