A bit of a heads up and FYI...
In Mozaix and Pantheon you can define and name net classes such as
"50_ohm", "audio", etc. Nets are then designated as belonging to one
of these classes by adding a property to the net called NET_TYPE and
giving it a value which matches one of the previously defined net
class names.

That's pretty straight forward and probably sounds familiar to many of
you. But there is an important item to watch out for... There are many
many places where you can add a NET_TYPE property to a net where you
are not restricted to choose only the previously defined class names.

Thus you can have a net with a NET_TYPE property using the value of
"50_ohms" and because the defined net class name is actually called
"50_ohm" without the "s" the net will be treated as if it is of the
default net type.

You won't get any sort of warning until you get into Pantheon and do a
DRC on the nets. Since most people don't do that until after they have
already been routing.... it could be too late. So run a net DRC check
periodically even if you haven't routed anything yet.

Greg