When saving a track template it seems outputs and sends to sidechain fx are not saved.
Is this as designed or am I doing something wrong?

Yes, it's supposed to work. If a track template contains sends, the referenced busses or aux tracks should be automatically created when you load the template. I just tried it, and although the bus was created and the sidechain target was inserted into the bus' fx bin, the send itself was missing. 

Thanks for testing!
 
I see same result both using sends and output to sidechain, lost when saved in track template. Tested also in 8.5, same result. To bad, makes track templates a bit limited. I guess nobody uses it as it was never noted.

Thanks its on the fixlist for the next release