2006 Jaguar XJ8 (X350) NA 4.2L; Transmission (TCM) faults investigation leads to finding a bad ignition coil

Wanting to share a finding I came across that may help others with similar conditions related to their transmission operation.
Condition occurs primarily after start up and most active during first 20 min.+ of engine operation.
Symptom: Aggressive transmission shifts experiencing in and out of gear shift condition in forward gears and reverse. Vehicle does not have to be moving. On occasion, condition may occur after warm-up under some load in traffic. Transmission shift can be harsh with a bang. As driving continues, conditions observed to subside. Transmission performance is very similar to perceived failure of ZF transmission seals to valve body and solenoid failures.
Keep in mind that the Instrument Cluster is our Gateway regarding CAN (Controller Area Network). The proximity of the Instrument Cluster to the found failure I believe may be relevant to the vehicle faults on the CAN system interacting with the modules.
I experienced fault codes over the CAN system between TCM, PTM, ABS Module, Parking Brake Module and Instrument Cluster. Most often not all the modules at once. All faults could be cleared. Fault codes related to loss of communication to/from TCM.
CAN system voltages test fine with CAN HI and CAN LO. 60 Ohms across the system as well. No short of CAN HI or CAN LO to ground or power. In general, CAN system backbone measures to be intact and functional.
No scope is being used to analyze CAN communication. A DVM used to test static condition of CAN system, a BOB (Break-Out-Box) for the ease to measure the CAN system backbone and the CARSoft interface tool to monitor signals of individual modules when system is in operation.
My initial focus was the TCM module signals as the fault codes lead to communication loss/interruption of modules with the TCM. No unusual conditions were observed other than momentary loss of signal from/to the TCM which I believe caused the other modules to show a fault as well when they could not communicate with the TCM. Undercar TCM/transmission connections physically were clean and dry.
During the monitoring of the individual modules over way too many cold startups, no abnormal signals were observed other than the momentary loss of signal which most often did not log a fault. My focus using the CARSoft tool went to the PTM module observing signals for engine function. Sensors read fine. I focused on the misfire cycle counter and the individual cylinder counter misfires. Misfires were being counted with barely a correlation of engine shake to the event. Individual cyl. misfire counters zeroed once misfire cycle counter read 4000. No misfire faults set. The focus went to cylinder 8 where misfires were counted. (Cylinder #8 Bank 2 is closest to the Instrument Cluster on LH drive cars as numbered with our engine family.)
I pulled the #8 spark plug. The NGK 5N10 plug was decent for its age/mileage. I wire brushed the plug as I had no spare and reinstalled. Restarted engine and noticed the misfire count was still occurring. Perceived to be less frequent though.
I swapped the ignition coil with cyl #6 coil. The misfires followed the ignition coil to cyl #6. Cyl #8 is fine now. Ignition coil is determined to be defective. CAN issues lessened with defective coil on cyl #6 farther away from Instrument Cluster. I believe the bad coil now farther away from the Instrument Cluster lessened the CAN issues. New NGK plugs and one new Delphi GN10448 ignition coil were installed. Operation of transmission/TCM as well as the other modules is normal and no CAN issues observed.