That is definitely simply coincidence. I have had dogs have runs on raw, back when I fed only raw -- if a dog has diarrhea, it has diarrhea and when it passes thru its system, it will improve. The fact that you fed bland food for a day probably did much to help settle the problem anyway (usually you need to feed for several days, not one meal, and after withholding food entirely for 12-24 hours). But the larger issue here is of a dog CONTINUING to get severe runs on and off.
I think that when puppies in particular have continuing on and off problems with diarrhea the first concern has to be diet.
Also if one chooses an entirely raw diet it is good to be sure you are aware of both sides of the arguments on raw. This is a diet surrounded by considerable controversy. I used to go for the argument used by pro raw feeders that this is all because vets don't know anything about nutrition but since, I have spoken to vets who actually get a fair amount of background in nutrition (as a journalist, I find it is often wise to check out claims rather than simply believe them). Also most vets will have stories of raw fed dogs coming it with intestinal punctures, bones lodged in or behind their palates, ripped anal tissue, and other serious problems, sometimes, resulting in deaths. I also used to believe the oft-heard raw feeder argument that more dogs choke on kibble but talk to a vet and this simply is not the case either.
So in trying to separate fact from hype, myth, and stubbornness, I have come around to having a lot more concern about raw feeding than the arguments against raw feeding. I know pro-raw holistic vets who have changed their minds on raw, from emergencies they've seen in their canine patients, and now feel there are risks to the diet that do not outweigh the possible benefits.
Gastroenteritis is considered to be a risk factor for raw.
Raw diets suit many people's personal philosphies on feeding -- but I do not feel anyone should simply feed raw without being aware of the possible risks and considering whether they are acceptable, just as with any aspect of dog care.
Some articles worth reading:
Critique by Dr John Burns of Burns holistic dog foods:
http://www.dogsey.com/dog-articles.php?t=8041
The Wikipedia article,
http://en.wikipedia.org/wiki/Raw_feeding , is actually quite good in presenting both sides and has good links for both sides and neutral articles.
Also:
http://www.workingdogs.com/portal/html/article.php?sid=33
http://www.woodhavenlabs.com/documents/feeding-raw.pdfhttp://www.woodhavenlabs.com/barf-myth.html
http://www.secondchanceranch.org/training/raw_meat/myths.html
The web is full of pro raw sites and lists for the other perspective. Just make sure you have weighed up the risks v benefits.