NA> When I use Pktview (util from '94) to view the packet sitting in Mystic's
 NA> outbound before its sent here, the packet header is showing as being from
 NA> the address 1:65535/426.93.
 NA> 
 NA> The negative Net display here is simply a cosmetic problem for me to
 NA> deal with but the unusual Net-value generated by Mystic in the packet
 NA> header is not.
 NA> 
 NA> I am not a Mystic expert or even aware if I am using the latest version
 NA> but this is what I have discovered in less than a half-hour of testing.

This is not an unusual net value within a PKT2+ packet.

In a PKT 2+ format if the origNet is $FFFF it indicates that the origin is a point system and the net is found in the auxNet field. 
Here's a paste from the PKT2+ FSC-0048 documentation:

auxNet field:
    When parsing a Type 2+ packet, if origNet is 65535, the software MUST use
    the value from the auxNet field.  When creating a packet, if the
    originating system is a point, it SHOULD set origNet to 65535 and
    put the net number in this field. 

The reason for this kludge is so that PKT2+ maintains backwards compatibility with PKT2 while also allowing for 4D addressing that was missing in the PKT2 format.

It may be that D'Bridge needs to be updated to support PKT2+ for point support for this to work.

--- Mystic BBS v1.12 A47 2021/04/08 (Windows/64)