Help with analyzing a primary ignition waveform 2014 kia forte

This primary ignition waveform is from a 2014 kia forte lx with 104343 miles on it.  This event occurred near the beginning of a snap throttle test.  Many of the burn lines during the snap throttle look like this.  This burn line is different than the burn lines at idle.  At idle they tend to rise gradually until the drop out and the "ring" is seen.  With this event the burn line rises then suddenly drops and then rises a second time before dropping out and the "ring" is seen.  Does anyone have any idea why the burn line would do this?  It almost looks like there are two distinct burn events in the same ignition event.  I have not yet replaced the spark plugs but plan to do so at 105000 miles.  Could this just be from old plugs?  Any insight would be greatly appreciated.  Captured on a Picoscope 4225A with a Pico 10:1 attenuating lead.

Thanks,
 

Sorry if this confused anyone. I added another capture with an example of it at idle for comparison.

Are you experiencing misfires or trouble codes that lead you to scope the ignition system?
The spark line changes under snap throttle due to changes in pressure in the cylinder. If the spark line looked the same during a snap as it does at idle, then that would indicate that the spark was escaping and not taking place in the cylinder at all. If there is not running issue, I would call it known good.

No misfires or trouble codes just curious if this could be an early indication of a valve issue or maybe just old spark plugs. I will be changing the spark plugs in about another 800 miles and will do another capture after that to see if anything changes. For now I will assume known good. Thank you so much.

One of them does look odd, to be sure, but my first thought was turbulence? Under a snap throttle.

I always thought that the variations you're seeing in the burn line are caused by turbulence in the cylinder. Seeing turbulence like that can be an indicator that spark is taking place in the cylinder, and that the cylinder has (some) compression.

I'd also count these as known good. Unless you see something different with the new plugs, in which case, please share.