Several possibilities in my view:
1. as he is growing his mental and physical exercise need is changing, u may want to look into adding some more fun to get him tired before bed
2. He may be in a fear period when they do change their minds about things. Again, try to see if u can add some more mental and physical challenges for him to get his mind away from feeling left out.
3. Again since he is at an age where he is changing and because vizslas are smart, the same motivator may not work, what worked for months. Find out what would be a higher level motivator than the current treat and toy to get to crate.
They are very good with telling us what they miss or dislike, we are just usually the ones who fail to listen, so try and figure out what your pup is trying to address. :-)