I'll start this off saying that I've actually sent in a report of this before, but unfortunately I'm not quite sure if it was ever posted. Granted, I'm sure it's because it's a bug that's hard to replicate on the bug testers end, or maybe I just missed seeing it posted.
I've been encountering this glitch where my plants of which are supposed to be Elder, end up restarting back to the beginning of their Mature stage when I go to harvest them. It doesn't happen every time, thank god, but it's happened about 12-15 times to me on various characters since I first had this happen.
Whenever it happens with my Couch Potato plots, usually a few are Elder but then the rest are started back at their Mature phase, and with my few Evil Magma Peas that I have, all of them are reset back to Mature. I've noticed that it usually seems to happen if I miss the exact Elder time by a few hours, although it has happened within a 3 hour time period since the planned Elder time.
Admittedly, I do keep forgetting to take photos because I keep getting irritated in the moment and then getting off before I remember, but I will say that missing out on 50+ mega snacks when you constantly keep gardening logs to make sure you're being as efficient as possible is quite annoying.
A few other things that I've noticed about it: 1) Logging out of the game and coming back on never fixes it, whether it be immediately after, an hour after, a few hours after, or even the next day (I ended up testing different times as it happened again) 2) Taking care of their needs and pests allows me to get a Mature harvest from them even though their progress bars are reset to the beginning of Mature (I'd like to say here that I do not calculate the times with the "time until harvest" on the gardening window. I'm aware that is for the Mature harvest and not the Elder, so it's not about that) 3) It's a bit weird about when the plants end up being Elder. Although usually I just take the time I checked it and calculate it as I usually would when it turns Mature from Young, I've accidentally ported to my barn before the calculated time a couple of times and they were Elder. It was a weird silver lining at some points. 4) I've never had it happen with any other phase change. Changing them to Young or Mature has never given me this glitch, only Mature to Elder. 5) Only once has it happened the other way around, where most of my Couch Potatoes were Elder while one was restarted back at Mature.
If it happens again, I'll try to remember to take a photo of the whole plot with some Elder and the rest Mature, and of the gardening window saying that it's the beginning of the Mature phase but I can harvest it. Maybe I'm just having really bad gardening luck or something, but I can't fathom that it hasn't happened at least once to somebody else. Either way, I hope that something can be done to see what's going on with my plants.
Yes. This first started happening to me several years ago. It has happened to me many, many times. I've discussed it with many people and most people seem to not have this problem but for those to those of us who do, it's incredibly annoying. It's hard to keep an organized garden when a random few of the plants never make it to elder and get out of synch with the other plants. Over the years I've learned that 1. It does not matter whether the plants are stacked or not and 2. it does not matter whether the plants had pests on them or not.
And yes, I believe that this has to do with how long after the elder time the plants are checked, and in my experience it can happen if the plants are left alone too long after they have reached elder. Too long isn't that well defined, it seems to vary, but it can be as little as 2 days in my experience. And often it happens only to one or two plants in the entire garden (that is a common occurrence with sunions). Other times I get a salt and pepper appearance with elder and reverted plants mixed apparently at random. Unlike the sunions, this does not often happen to my couch potatoes or evil magma peas, but it has happened to both of them, more often the couch I think. And yes, the plants that reverted to mature can be harvested even though they are showing many hours until harvest.
It may be related that I also have had issues with sunions if I leave the plants alone for more than 2-3 days during the mature phase. Even though I leave them with no needs, some of the plants can be dying if I return to check them after loo long. That's not really an issues with couch potatoes and evil magma peas because they elder a lot faster.
