I recommend the following:
Gather wellhead amps and volts or VFD output volts and amps. Multiply them together and divide by 746. HP = (Volts * Amps) / 746
Now plot your horse power as a function of time.
By looking at any common radial flow or mixed flow pump curve, we can see that if fluid flow through the pump also increases, the brake horse power also increases for the majority of the operating range.
Therefore, if you have a hole in your pump housing, discharge head, or tubing, the flow rate is going to increase and motor horsepower will increase regardless of surface flow rate changes.
If you have a plugged pump discharge or tubing, your flow rate going through the pump will be zero, and the motor HP will decrease.
If you had a twisted shaft and not able to develop enough head to lift the fluid to the surface, the flow rate will be zero the motor HP will also decrease.
I would ASSUME that since you have a higher end sensor with discharge pressure, you also have a motor oil and possible motor winding temperature sensor. What are these readings telling you?
The motor controller is usually designed to shut down the ESP in a high temperature condition. If you have no flow through the pump, and no auxiliary recirculating equipment, your motor temperature is going to spike up and the pump will shutdown on over-temperature. If you never had an over-temperature shutdown, it is likely that you have a hole in your tubing.
When you say tubing pressure do you mean actual tubing pressure on top of the well or do you mean flowline pressure? Another small thing that can happen is that you can have a casing check valve that gets stuck open allowing fluid to circulate from the christmas tree on the surface back down the annulus. Though, I'm not really familiar with running gas lift and packers in combination with ESP equipment. If you had a packer above your ESP, I can't envision that you would also have a casing check valve.
There are a whole lot of problems that can occur when running ESP equipment. They can accidentally run the wrong pumps with the wrong stage design, run the wrong number of pump housings, or switch the order of the pump housings on tapered ESP designs.