Customer had auto-configured interfaces for PPPoE/DHCP subscribers with underlying psx interface. When he tried to move the already created VLAN interface to a static configure with differrent family, the bbe-smgd keeps core dumping and affects the other subscibers.
For example:

lab@bng# run show subscribers stacked-vlan-id 1001 vlan-id 1 
Interface                       IP Address/VLAN ID                      User Name                      LS:RI
ps1.3221225481                  0x8100.1001 0x8100.1                                              default:default      
pp0.3221225482                  100.104.0.3                             pppoe                     default:default  

[edit]
lab@bng# show | compare 
[edit interfaces ps1]
+    unit 10010001 {
+        vlan-tags outer 1001 inner 1;
+        family inet {
+            address 192.168.2.1/30;
+        }
+    }    

[edit]
lab@bng# commit 
commit complete

[edit]
lab@bng# 
Message from syslogd@bng at May 13 07:19:48  ...
bng bbesmgd[21166]: ../../../../../../src/junos/usr.sbin/bbe-svcs/smd/infra/bbe_ifd.c:bbe_ifd_add_vlan:7802: insist 'itable32_lookup(myTable, &vlan_tag_id) == NULL' failed

Message from syslogd@bng at May 13 07:19:54  ...
bng bbesmgd[23122]: ../../../../../../src/junos/usr.sbin/bbe-svcs/smd/infra/bbe_ifd.c:bbe_ifd_add_vlan:7802: insist 'itable32_lookup(myTable, &vlan_tag_id) == NULL' failed

BBE-smgd core dump

There has already a check to handle static configuration of vlan interface if it is already being used by any dynamic interfaces. But the ps interface doesnt have this check.

PR1810393 has fixed this issue. With the fix, customer can configure the static vlan interface, but it will function only after the already online dynamic interface is disconnected.