Hello again.
I managed to reproduce an issue with this plugin parameter. It didn't present itself in the exact way that you described, but if nothing else, it was definitely contributing to the problem. In my test project, I had a recipe that should have given 25% hp recovery and +60 flat hp from the traits, but it was actually giving 39% and +240. This was regardless of how many times the item was crafted. The issue ended up being some logic I had programmed incorrectly that was only used specifically for the skyrim-like system, which was causing traits to be combined with each other far more than they were supposed to be. With my recipe it was 4x because the two ingredient items shared four traits with each other, but yours could've been different here.
Once I corrected that logic issue, the traits were added to the item in the correct amount, so it appears to be functioning the right way now. Let me know if you still have issues when you download the update.
~Ramza