Hello,
I have first report that to Industrial Foregoing (InnovativeOnlineIndustries/Industrial-Foregoing#535) but the dev say the problem came from SimpleHarvest and it can't do anything about that.

Basically the Plant Interactor do a right click on plants (This is what's the docs say about that machine...). This work with Vanilla plant's how right-click to harvest work directly on my mdoapck, but, with plants configure on Simple Harvest, the plants drop (+ the seed) is adding each refresh to the machine inventory, but the plants is never really harvest...

I have a demonstration video of what I say: https://clips.twitch.tv/SmallPuzzledSamosaTBTacoLeft

Simple harvest is set the way to don't get more seeds, but, like you can see, with Mystical Agriculture plants I always get a seed (And the mod is configure to NEVER drop a second seed, so here a big Dupe Bug!)...

I have try all other mods for harvest but only yours have good configuration and can work with all plants in my modpack, but yours is the only one having that issue with the Plant Interactor.

I what to know if you can do something to fix that issue, because now, my only solution to fix that big Dupe Bug with Mystical Agriculture is, one doesn't have Right-Click to harvest for XL-Foods Plants (I think, this is really annoying), or completly disable that amazing machine, but it work amazing for everything else. Or third possibility is to find another dev to make mods configurable but how work great with that machine (How is not really easy, because my name is not Darkosto)...

Fireztonez