I have read some say that the efficacy of one GLP is decreased by another - to be honest though, not sure how true or sensible that is given that the same receptors are being targeted, but who knows. No research has been published on the subject. Just anec data.
We have no idea what the outcome is outside of anecdotal reports. No studies are researching what happens, we have no human clinical trial data around it, etc. We know that stacking multiple types of the same drug is often a bad thing. The receptor agonism is balanced in a specific way with the formulation of the drugs in general. Is it safe short term? Long term? What side effects are there?
Lots of people seem to be doing it just fine, so maybe it is fine. But maybe it isn't.
As others pointed out, No studies indicate either way. My research leads me to my own research use. I, personally, anecdotally, don't want to over load receptors, with the same chemical, from 2 items. It may be moot, or not, but that's what my conclusion is, for me. Many research the opposite, and that is good for them. There's no way to tell. Grey research is diffrent for everyone.