8 digit Talk Group numbers in the Radio

Valid TG Numbers range up to 2^24= 16777216

I and a lot of others use a modified DMRGateway that allows the following

11XXXXXX = Net 1 BM
....
14XXXXXX = Net 4 TGIF
15XXXXXX = Net 5 MNET

ie Dial up 14031665 on the radio to use TGIF 31665.  The 14 prefix locks in Network 4 so a gateway rule of 
TGRewrite1=2,1000001,2,1000001,5599999 allows use of 7 digit talk groups on network 4

7 digit talk groups are abundant on TGIF

However when I use the 8 digit talk groups, it will not show the user callsign, instead shows the talk group ID as follows



Added....

Just discovered the same effect when using the standard 7 digit DMRGateway talk group id's