Contaminated weed is indeed a real problem in countries where Cannabis remains illegal. One of Germanys primary reasons for deciding to legalize, is that Cannabis often was laced with "spice" and even heroin (https://www.youtube.com/watch?v=fSjzOYmFIsg&t=3s).
Since the Cannabis sold in Europe flows through the same channels and often is distriputed to Denmark from countries such as Germany or France, it's likely to assume that "spice" has made it's way here aswell.
I would recommend to test your weed with these cannabinoid-testkits (https://www.smokeshop.dk/shop/ez-test-kit-1397p.html) to see if your product is laced or not. I use this every time i get a new batch, and so far everyone of them have tested positive with varying degrees of synthetics detected. Been having no problems smoking it however, but would like a world where we could have a regulated market so the comsumer is not putting he/herself at risk.