Cylinder 2 misfire and rough idle immediately after spark plug service, dealership says ignition coil has 0 voltage

I'm looking for some mechanical insight because I'm trying to understand what could have caused this issue.

Recently took my 2022 Subaru WRX (57k miles) to a local Subaru specialist shop for routine maintenance:

• Spark plug replacement
• Transmission fluid and differential fluid service
• Oil change

All parts and fluids used were OEM. Before this service, the car was running perfectly. I don't beat on it as it is my daily, but no check engine light, no rough idle, virtually zero issues as I took it in for maintenance.

After picking up the car the next day, I drove roughly less than 10 miles to get dinner nearby and didn't notice any issue whatsoever. Afterwards though, when I was leaving, once I started up the car, I immediately noticed the engine had a rough idle and would not settle down even after letting it sit for 10 minutes. I was then advised by the shop owner that it could be the ECU relearning itself after he removed the battery, and suggested I drive a bit longer. Not even after 5 more miles, I felt a sudden loss of power and what felt like a cylinder misfire, along with a lit-up dashboard.

I confirmed at a Pep Boys that the CEL threw a P0302 and P219A code. After sharing this with the owner, he suspected that the pre-gap could be off and asked me to wait 2 days for him to double-check.

After bringing the car back to the shop, they looked at it for about an hour but weren't able to give a clear diagnosis. They suggested the misfire was separate from the recent job and might be caused by:

• Carbon buildup on the intake valves, which requires walnut blasting, or
• Possibly a fuel injector issue

These were suggestions from individuals who were not affiliated with the shop but were present when I was there. Even the owner mentioned it was something they hadn't seen before and suggested that I fill up the car with gas and if the issue comes back, then it would most likely need walnut blasting.

I did what was recommended, and the issue persisted, which prompted me to go to a Subaru dealership for a second opinion. The technicians found that cylinder 2's ignition coil was receiving 0 voltage and that its wiring was pulled out.

I've attached the recommendation from the dealership, but since this was my only mode of transportation and the dealership was able to provide a rental, I didn't feel like I had much choice but to get it done right there and then.

With all that context, I wanted to ask:

Is it possible that since the wiring from the ignition coil was loose and I drove it, it could have caused a short circuit and ultimately the misfire

Any insight would be appreciated because I'm having a hard time accepting that the WRX would develop a misfire after receiving what should have been normal maintenance.