Lightning network nodes do not report Bolt9 functionality

Looking at the explainGraph command output for my node (LND), I see that my node is detecting about 19,000 nodes. Of those 19,000, 6,000 did not report bolt9 functionality.

lnd@node:~$ lncli describegraph | grep -c "features"            
18969
lnd@node:~$ lncli describegraph | grep -A 1 "features" | grep -c }
6274

Is there any logical reason why this could happen? In order to use the protocol correctly, we considered it essential to report the implemented features.