2016 platinum reverse NOISE only cold/first start

2016 Ford explore platinum 50,000 miles just had transmission flushed and PTO serviced by my Ford dealership and now when shifting in reverse on the first start up of the day or when the car is really cold I get a vibration noise from the transmission in reverse only in reverse, only when the transmission is cold is this the torque converter failing? This was not an issue until after the transmission was flushed by my local Ford dealer. No issues when brought into Ford just wanted preventive maintenance done on my PTU and transmission as well as the recalls. now I’m frustrated what’s the issue here? https://imgur.com/a/rn6lseL