600W HPS bulb randomly blinking every few min?

I need some help. Just finished setting up new grow area with two 600W HPS. Each have a 600W Digital Greenhouse ballasts (China made w/ fan). They've been run for a couple months each without any previous problems. I screwed in a new Plantmax bulb a couple days ago and fired it up for testing and it seems to flicker every 1-5minutes. Sometimes a few times a minute. It is not so noticeable that you can see it from a distance, but if you really focus, you can catch it flashing almost like a blink. I hear a small tick at times with it blinks out for that tiny millisecond. The hoods are both Yeild Master 2 w/ 6 inch are cooled having air sucked out through a 400CFM fan. I dont know if this is a hazard? Something with the bulb? ballast? hood? socket? The hoods are the first time I have run them, same with the socket. It is plugged into its own dedicated outlet which has a 20A breaker so I know lack of power is not the issue. I am waiting for a second bulb to do a test to see if the bulb is causing it but until then it is a bit nerve wrecking. Any advice?

best to be on the safee side.return it for a new one.doesnt sounds safe

I thought it might have been the socket because I was hearing a ticking/clicking noise by the socket everytime it would blink. I opened it up and disconnected the connect and switched the bulb over to the 2nd ballast and second hood and having the same issue! I ordered a new socket already so I might as well switch it out.