The answer is it depends. In reality every environment has a blend of yeast and mold spores. Each is different. Heck, even people nave a biome. There is talk of using biological signatures like fingerprints to uniquely identify peopleSo will it (mold) happen every time? My wineador is around 67% @ 66 F but my desktop is 72% @ 70-72 at the highest. It used to hover around 68 or so using 4-5 72% boveda packs. I put a cigar oasis ultra in the lid and now it is solid 72%. I have the Cigar oasis set to 70 just to bounce back the humidity. Is it just a matter of time? Room ambient is 30% or so.
I would take all your sticks out and store em in a tupperware for a week or two and re-season both units. I would also try the dollar test on the seal rather than just the drop test. Take a bill and close it halfway in the humidor at all different locations (i.e., front, sides, by the hinges and in the back) and pull the dollar out slowly. If it slides out too easily your seal may be bad (it should be slightly difficulty to slide out). I would also get a calibration kit for the hygro's and re-calibrate just to rule them out (preferably a dual calibration kit, one at 75% and another at a lower RH; Boveda sells two-point calibration kits). Will just take some more troubleshooting. You never know until you try and rule each thing out at a time. However, if you are maintaining 63-67 or 69 RH I would not even bother doing anything except re-calibrating your hygros. Thats a perfect RH, and as others have said the 70/70 rule is BS. Lower RH is definitely a better way to go for storage. Safer in the long term and smokes better in the short.Oops I edited that post a couple times and left out that yes, I’m using Boveda packs. The hygro is a decent digital one (I’m not near it right now). The humidors were seasoned with 84h Boveda packs for a week until they were holding high 70s humidity steady. Both humidors are close to full. The sticks are at most a few months old. All were shipped in cello and I keep them that way in the humidor. I live in Pittsburgh, the room temperature is in the low 70s. The bigger one was holding steady around 69 and started dropping. The smaller one I’ve always had trouble with. I use more Boveda packs than suggested for the amount I am storing but it doesn’t help. The fact that I am putting scotch tape all around the humidor and it’s not helping
Is really perplexing me. When the small one would get really low before using the tape I would wet a piece of paper towel and put it in there that would shoot it up for a day or two. The humidors are less than a year old and when I do the drop test it sounds like a good seal. The tape is just an experiment that obviously is to working