Try narrowing it down some to get fewer property choices.
This one gets you a 50% for Tier 2 dex at least a bit better than 20% chance.
I only played around with it a little bit, I'm not sure you can get it down to Just the dex choice. But with the ingredients I had it was the best I could do
They have stated that in future updates you will be able to select which one you want. Currently it randomizes among the ones you light up, but this will be changed. So it's not really a "bug".