Rosemount 3051CD transmitter mA output affected by 475 HART communicator

raw video: When "communicating" with a Rosemount 3051CD3 transmitter using an Emerson 475 HART communicator there was a small but easily measurable drop in the mA output signal.
At the start of this clip the transmitter had already been Zero Trimmed and the applied DP is 0.0" H2O (xmtr ranged 0.0"-69.1" = 0.0-15.0 MGD : Square Root Transfer Function). The mA output is slightly high (around 4.007mA) with the communicator offline. I was going to perform a D/A Trim when it was discovered that going online with the communicator caused a change in the mA output. When the transmitter was communicating the mA output signal dropped slightly; from 4.007mA down to 3.992mA. The same change in mA occurred at 12.0 mA (-0.014mA) while at 20.0 mA the effect appeared to be slightly less (-0.008mA).