Don't know if this is a bug or intended but here the report is and the steps to reproduce
- Have a full inventory
- Have the forageable you want with the quality you want.
- Pick up the same forageable.
- If it rolls the same quality as the one you have in your inventory you will pick it up.
- If it doesn't the game will say that your inventory is full.
- Repeat from 3 until you roll the same quality