I originally reported this to Vanilla Backport, since I thought the Wildflowers were the culprit, but Pink Petals from the base game can also be duplicated with the Wrench.
I think a solution would be to make it so that additional individual property names can't be modifiable, or a quick-fix by making the Pink Petals not modifiable in the tags.
Steps
- Place 1 Pink Petal
- Switch to Wrench and cycle to "flower_amount"
- Set "Flower Amount" to 4
- Get 4 Pink Petals