Have had lots of splats in the past from the non-emissions rated engines, but globs of black gunk instead of this. And both my Kubota CUT's, L3710 former, L5740 current (Tier 4 interim) put out enough black soot on start up to clear the home 40 of mosquitoes.
The whole reason for a DPF to be on a vehicle is to PREVENT soot from being admitted to the atmosphere.
Something definitely went wrong there, based on the evidence, the DPF failed due to overheating. Lots of potential reasons for that, most common is an over-soot event from an operational or maintenance failure.
/ Violent Diesel Regeneration (?) Threw up on new car
regen should not have been taking place at a stop light, road units do this at a minimum speed to prevent stuff like this. i remember a story about when ford was developing their system a truck melted down some black top