Minecraft v1.12.2
Forge v14.23.5.2838
Inspirations v0.2.5
Quark r1.5-168

If I right-click sugar cane two or three blocks up from the ground, the seed gets replanted on top of the sugar cane block.
Quark is the mod I'm using for right-click harvesting.

If this needs to be reported to Quark, I can do that as well.

Can you post a screenshot to show what you mean? This sounds odd to say the least.

Also, have you modified the Quark config at all? Last I checked it did not automatically determine drops but its all config based.

The sugar cane seed got planted on top of the sugar cane plant.

Fixed in latest Quark