This house was created in the app and I was able to confirm it. However, it’s slightly away from it’s correct location, and the editor won’t let me move it because it has a (correct) non-numeric house number.
From my experience I’d say that’s an old bug as the WME seems to not accept any HN that contains more than just digits for RPP. So either remove the trailing letter and correct the position or - if a navigation would lead to the correct destination - leave it untouched.
And I bet as long as it isn’t something like Downing Street 10a it’s not that important. 
Waze’s obsession with the concept that houses can only have numbers and not names is a pain in the proverbial.
Particularly when the validation is different in the app (allows 10a) and the editor (no alphabetics whatsoever).
When I need to name a house, I create it as an “other” and put “residential property” in the description.
I second your complaint in general. But I’m not sure if it’s the right way to fix one wrong thing with another, especially I don’t like the idea that your way the RPP might show up outside the search for that special place then.