REGEN ISSUE: DOSER OR OTHER?

Have 2013 Pete 587 / Cummings ISX.
82k ago - Replaced DPF Filters. after having Regen issues that threw codes. Work done, software updated to account for replacement - sent me on my way
Also had issues with Thermostat and Gasket Housing... they claimed it was related to the regen issue
Short time later (3) mo's DPF injector no response... Different Dealer - while inside shop, they replaced the DPF Injector, Doser Valve was very sooted, and clogged, they put new one on and once again cleared everything and tested it. All good. Now have another issue I need feedback to know if they are related.
Truck is Showing "Regen Required."
Passive Regen will occur,,, noting the slightly higher idle while parked or stopped at lights.
When I start Parked Regen... Takes 20mins before temps get hot enough to display "High Exhaust Temp" and goes out 20 mins later. Regen Required is still Displayed with no CEL
2 days ago had CEL... and code pulled was "too frequent regen intervals."
Had codes cleared and returned as no relevant data to acertain the reason showed up using JPRO.

I am trying to figure out if there is a sensor bad... or Injector clogged up again. I feel like the temps in the DPF arent hot enough. Any Ideas?
As a point of follow up... Currently in Regen (Parked) and High Temp went off after 30 mins, but the Regen itself is still going. Timer is on 2hr:15 mins

 

Have currently 642k
haven't had any serious issue other than this. I am hoping the Filters aren't clogged already causing this issue cause Baking them is expensive and I have been told you should get better than 82 out of them (Brand New) If they are... well that means overhead work.. Which case - Truck is done

 

I have one... Just quit a month ago....
The #### thing shuts down after 2 mins... cause the generator itself went.

 

I have little to go on with your theory other than you might be "partially" right.?
As for consumption.. Oil - 2 gallons between changes. which i try to stick with 15k intervals... fuel 6-7 mpg
no consumption with coolant. And I haven't had the top of the engine looked at yet... that's where your probably partially right.
Meantime... I am trying to get one problem handled first then gut the bigger fish