[Ifurita]

I'm not too experienced with Pings, but perhaps the issue here is a lack of air circulation? You did say that previous successful attempts did not involve a cover but this one did so perhaps that's the issue?

Just like you, I also grow P. primuliflora and it produces plantlets which I just take and place on similar media when I feel like it, but I've never had them rot. Just like you too, I don't cover them either(sun and water vary).

Just wondering, but this is the typical P. primuliflora, right? I've seen what was claimed to be the rose form(can't say for sure since it wasn't in bloom), but that primuliflora's leaves were a little different and seemingly more fraglie...so perhaps different clones of P. primuliflora have slightly different preferences/tolerances. That might explain why Jeff thinks its eratic while I'd say that its easily the most fuss free Ping I own...