2012 International prostar shutting down

Hi...new to the forum...have a 2012 international prostar with maxxforce 13...we bought in august...after running for a month it started shutting off (once a day) when the operator took foot off accelerator..for ex...slowing down at intersection...driver had to wait 2/3 minutes until it would restart...
Since it originally started occuring this same issue continued and became more frequent...we had the truck to shop several times and have spent several thousand trying to source the problem (changed temp sensors/filters/coolant sensor/air to air/ecm)
Any suggestions appreciated

 

Indeed...still like to figure it out tho