Voltage dropping on Pro

I have read that page over and over and none of it helps. It does not explain why my voltage is steadily dropping. I had my transformer installed by an electrician who has installed many Ring Doorbells and he also checked my wiring. I Wish I had gone another route with Home security and probably will and when this doorbell fails as I am sure that it will I am going to cut my losses and invest in security cameras and/or doorbell that works.