The coasting link is interesting. I have Tucson PHEV and have never had the PPF issue (famous last words) but I use Apple CarPlay instead of the in-car sat nav, so coasting never kicks in.
There is no coating on the non hybrids and believe its turned off by default on those that have or does the PHEV, Hybrid 230 seem to have the same problem.
How many electric miles do you get and whats your mpg on longer runs in hybrid mode?