Apparently this stuff has to be carefully stored and has a shelf life ?
I've seen nothing to suggest that Adblue is any more complex than a simple aqueous solution of urea - see:
I think all the other metals etc listed are just maximum permitted impurity levels, since the minimum of each is zero.
I'd expect that if the Adblue got too cold then some of the urea might precipitate out because the solubility limit would have been reached, but without checking the solubility curve for urea too cold is probably a pretty low temperature.
We used to dissolve and use 8M urea (480g/l IIRC) in the lab often - it's a standard reagent for denaturing proteins.
This doesn't mean that a concentrated urea solution doesn't degrade if stored long-term, especially at higher temperatures or open to the air so that eg CO2 can be absorbed, so unopened shelf-life can still be important.