I hear a clicking noise coming from the driver side door or wheel. It starts as a click, click, then it steadily gets faster and then goes away. Usually does it going up hills or grades. It’s quiet but noticeable.
I believe this is the same noise my 2016 with the 3.6 makes. To me it just sounds like the engine under load going up hill. Not really engine lugging, but some clicking noise of some kind. I think you hear it from that area of the vehicle since it is least noise insulated around the fender. Only happens when running lower rpm's in higher gears like 7th or 8th gear up hill (50-ish or more MPH). Once it downshifts it goes away. Also like you said it'll go away on its own after some time. All of these motors make more or less noise but it's normal. It'd probably be less noticeable in sport mode, or if jeep made the throttle and transmission a little more responsive, to mask the noises the engine makes in that scenario. But these vehicles are programmed way towards fuel efficiency which is annoying living in a hilly part of the country.
It's gone 90k miles with it so far, the sound hasn't gotten any worse or more frequent, so I ignore it