I have many stacks like this and have tested a couple... I'll describe the quirk using Bright Blue example... I have 3 bright blue Rushes and collect all seeds and they stack via bag method... I now have a stack of 24 "Blue Rushes Seeds"... they lost the "Bright" label but I can see they're bright so I really don't care that much. I collect seeds from plants that were crossed to make rushes and I now have a stack of 8 "Bright Blue Seeds" that don't say they are Rushes but they are. I use Poppy dust on my stack of 8 and now have a stack of 8 "Bright Blue Rushes Seeds" and a stack of 24 "Blue Rushes Seeds" that are, in fact also bright but not labeled that way. The two stacks won't combine. Ugh.... I use Poppy Dust on the stack of 24 "Blue Rushes" seeds and they get the "Bright" label back and now stack giving me one stack of 32... I've tried this on many stacks... I just used this one example to illustrate what's going on. Let me know what you all find.