I've shot a number of dirty powders over the years and cleaning for me is something done after every range/field trip without exception, then at least once a month thereafter. I appreciate my firearms enough to ensure they look and function properly.
The load data I used was in Lee's manual which is taken from the powder manufacturer's data. The only new variable was in this case the powder. The load was a starting load +.2 gr., no flattened primers, no cracked necks or bulged cases. Clearly however something went wrong for fouling of that nature to occur and that is the only reason I discontinued use.
I'm sure others will shoot it with no problems, just sharing my experience (sorry if I cast a negative tone, neutrinos have damaged my sensitive side; )