The bolts on your bar sockets may be over-torqued. And you should absolutely lubricate the sockets! I know it sounds counter-intuitive, but here is the exact wording from page 23 of the Owners's Manual, "The friction surfaces of the head and sockets should be kept clean and well lubricated with a good quality lubricant. They should be lubricated before each trip. Check for damage or abnormal wear at the beginning of each towing day and replace if necessary. Use a rag to clean dirt and road grit from all friction surfaces regularly.
All nuts and bolts should be checked before each towing day and retightened
or replaced if necessary.
If you don't have the Owner's Manual, you can download it here: http://www.equalizerhitch.com/pdf/eq...anual_0111.pdf
Hope this answers your question and solves your problem!
2015 Jay Flight 32RLDS Elite
2012 Chevy 2500HD Crew Cab LTZ (6.6L Duramax/Allison)
Equalizer Hitch (1200# bars)