A Power Issue?

I have been working a problem ticket for the past couple of weeks. It is tracking the constant bouncing of circuit feeding one of our remote sites. An issue with the lines from the building to the pole has been resolved by the utility company. Also the batteries in the ups that our equipment is plugged into have been replaced. I thought for sure that we had this issue pegged.

As a requirement for problem tickets, I have been monitoring our remote equipment to ensure that the issue has been resolved. In my monitoring I have found that there have been periodically incrementing output drops on the WAN interface of our main switch at the site. My initial thought was over utilization of the circuit, but I did not find any in our monitoring tools.

I then called the Vendor. I wanted to know if they could see any over utilization on the circuit. What they found was the exact opposite. They found that the connection has been dropping between their equipment and ours. They found that their Adva’s logs are showing dying gasps alarms every two days right around 16:50 each time. Our equipment has been up since the site transitioned back to commercial power early last month(I check the uptime every morning).

My hypothesis is that there is an issue with the UPS that is causing the power to fluctuate enough to briefly effect traffic but not enough to register as a power hit. One of my colleagues has suggested it is an issue with the Vendor equipment. What do you guys think?