On MX platforms slow show commands response when "AFT based module" has traffic manager mode ingress-and-egress configured.

AFT based module, which includes MPC10, MPC11, LC9600 and MX304. 

On AFT based module, which includes MPC10, MPC11, LC9600 and MX304 with traffic manager configured under FPC stanza, slow response(takes around 10-15 seconds) will be seen when running show interface <interface> or monitor interface commands and show interface queue does not work.

user@mx# set chassis fpc 0 pic 0 traffic-manager mode ingress-and-egress

user@mx> show interfaces queue et-0/0/0

Egress queue statistics are not applicable to this interface.

"traffic-manager mode ingress-and-egress" command is used to enable ingress-queuing on an FPC. This ingress-queuing feature is not supported on AFT based module, which includes MPC10, MPC11, LC9600 and MX304. So need to remove the ingress queuing related commands (mode ingress-and-egress, ingress-shaping-overhead) from configuration.

NOTE: Committing changes to traffic-manager automatically restarts any necessary components (PICs, DPCs, or FPCs).
Refer below link:
https://www.juniper.net/documentation/us/en/software/junos/cos/topics/ref/statement/traffic-manager-edit-chassis.html

But MX304 change traffic-manager setting won't restart FPC automatically and needs reboot system to let configuration change take effect.