I'm playing on the beta branch using the compatible DFHack branch.

Using the current stable version of DF, I can't replicate this behavior.

The dyes from Expanded Dyes are milled from plants, so this is what I've tested:

In quern:
Generic reaction: Mill plants into dye - Works
Mill dyes: Mill mint dye - Works
Mill dyes in bulk: Mill 30 mint dye - Works

From workorders menu:
Workorder (Quern specified): Mill 30 mint dye - Works
* Condition: Amount of unrotten meadowsmint at least 30
* Condition: Amount of empty bags at least 1

Workorder (no specific workshop): Mill plants into dye - Works
* Condition: Amount of unrotton DYE_MAT plants at least 10
* Condition: Amount of empty bags at least 1

Workorder (no specific workshop): Mill mint dye - Works
* Condition: Amount of unrotton meadowsmint at least 1
* Condition: Amount of empty bags at least 1

Which version of Dwarf Fortress are you playing on?

OK. I actually uninstalled all copies of all my mods just to make sure everything was clean and non-conflicting.

The only mods I used in this save were, in load order:

Expanded Dyes
AA
Days Til Harvest
Expanded Dyes Patch (this mod)

I've also tried swapping AA and Expanded Dyes, with the exact same results.

After collecting 10 of an Expanded Dyes plant, I queue 1 manager order each of milling plants and milling plant growths. The "mill plants into dye" manager order fails a little more slowly than the "mill plant growths into dye" order, but the "generic order" option directly on the quern still won't let me mill plants/plant growths at all so it's clearly still not finding the plants.

The *only* thing I can think of at this point is some major kind of user error. Or I'm missing a companion mod that's accidentally a dependency.

I'll gladly send over my save file, but I don't know if looking at my save can fix PEBCAK...

As long as Expanded Dyes and any civilization mods are before this patch, the load order shouldn't matter. I typically load AA after any other plant mods just in case, so my load order would be:
Civ adding/altering mods
Other plant mods
AA
AA configuration mods (Days Til Harvest, etc.)
AA civ compat mod
AA plant compat patches (Expanded Dyes Patch, etc.)
ABV

Hey Droseran, I'm still having the same issue as before across every single fort. Is there maybe a preferred loading order between AA, this patch, and ED that I maybe missed? I'm stumped and I just want to automate my dye milling again!

I looked over the raws and they're defined exactly the same as the vanilla dimple cup. I'm not sure what could be causing the issue you're having, but if you're getting cancellation messages it typically means the workorder can see the stock, but the stock is not available to the workshop.

I have a medium-sized issue with this mod. I try to create work orders to mill X amount of dye from plants/plant growths, and it returns a "no plants/plant growths available" cancellation no matter how many of the special dye plants i have in my dye stockpile. It's not a barrel access issue, either. So far the only dyes that I have successfully created through this work order are ones that are made from the vanilla 4 dye plants.

Are the dye plants being given all the correct plant tags? That's the only thing I can think of that may cause this problem...but I so rarely edit RAWs that I don't know how to check that.

Oh wow thank you that was fast