I've managed, over the years, to do various (unintended) mixes and the results have been quite varied as a function of the materials, weather and other factors.

In general, I ended up with unbonded, soft and/or sticky masses that were a royal PITA. One combination became amazingly brittle and hard as well. I learned to be a bit more careful in setting up mixes and materials (G).

I have his terrible disease called "stickraphobia" so gummy, never curing masses just about send me over the edge (OTOH, young mothers love me because I was kid hands often (G)).

On the whole, I don't trust the bond or mix that I'd get from those kinds of mismatches.
geoff