The fact that some of these MPs do point to actual correctable problems does little to convince me that they aren't still being generated by old data. It merely means that in those cases, no one caught the problem before. In the Los Angeles basin, I close between fifty and a hundred of that particular variety of MP every week. A great number of them turn up where alleys were previously set as service road type (no routing penalty difference from regular street segments) instead of parking lot or private road type. These are often in repeat locations, where I changed the road type myself in response to a prior MP or UR. If Waze were actually routing users down these alleys still, as the MPs suggest, then I would expect to see the occasional UR submitted by a driver, but I don't. One could argue that drivers don't bother to report, but the high frequency of URs popping up in places where the road type IS set wrong would back up my thesis. These MPs are still using outdated drive and routing data. Note that they always appear in red, as if they are aging map issues, never in yellow or orange, like newer ones do. I come upon an equal number of automatically generated "restricted turn might be allowed" MPs, and these always start out in yellow. There may be some question as to whether Waze will occasionally have a routing failure and send someone over a parking lot road segment mid-route, but I have documented occasions where these MPs show Waze routing over roads that have been deleted or separated well over a month before the MP shows up.
See my example in this post:viewtopic.php?f=8&t=49135#p440491
What's most frustrating about these is not the fact that I have to waste time closing them again and again, but that newer editors who are unaware of the old-data issue find them and try to fix problems which no longer exist. This is a big problem in LA, where we have wave upon wave of new people trying out WME on a weekly basis. I find myself locking things which shouldn't need to be locked, all because Waze keeps generating these MPs where all the issues have been dealt with, and nary a UR ever shows up.