Hello ,
This configuration change should not cause connectivity to the Gateway for internet . It looks to be some kindof communication issue between the Switch and the SRX ports realted to VLAN ID change .
So If you can aford a downtime , kindly do the following : ( It will impact normal traffic )
> restart interface-controller .
If that does not help , make a dummy change like :
# set interface st0.0
# commit full
Do a "commit full " this will restart all the deamons and hopefully it will get resolved with reload of the devices .