Before dissing the op's gear, do a little research. The AVS 2000 is not like your typical line filter that simply provides a little surge protection and does no voltage correction. The Monster unit has a computerized servo motor connected to a variable transformer. It's like an automated variac. This provides both overvoltage and undervoltage protection (between 80V and 140V). I can't comment on how good surge protection is without doing more research.
If you have 3 of these units and only one is reporting 130V on the output, then that is not a line voltage issue. If the voltage at the panel was an issue, all 3 units would be reporting the same overvoltage on the input. Since this is only on the output of one unit, the issue is with that unit.
These units have dangerous levels of current. Do not attempt any repair unless you have a lot of experience repairing electronics. The problem you will have fixing this is that Monster does not release service manuals. You might find a repair shop willing to look at it, but without a service manual many shops won't touch it.