Unable to filter for "out-interface"

Hi folks,

I use the below router.

Model: RBD53GR-5HacD2HnD
Serial Number: router
Firmware Type: ipq4000L
Current Firmware: 7.6

For some reason, I cannot filter the print output by out-interface.

[admin@router.router] /ip/firewall/nat> p
Flags: X - disabled, I - invalid; D - dynamic 
 0    chain=srcnat action=masquerade out-interface=ether1 

 1    chain=srcnat action=masquerade out-interface=lte_default 
[admin@router.router] /ip/firewall/nat> p where out-interface=ether1
Flags: X - disabled, I - invalid; D - dynamic 
[admin@router.router] /ip/firewall/nat> p where out-interface=lte_default 
Flags: X - disabled, I - invalid; D - dynamic 
[admin@router.router] /ip/firewall/nat>

But other fields work as expected.

[admin@router.router] /ip/firewall/nat> p where chain=srcnat 
Flags: X - disabled, I - invalid; D - dynamic 
 0    chain=srcnat action=masquerade out-interface=ether1 

 1    chain=srcnat action=masquerade out-interface=lte_default 
[admin@router.router] /ip/firewall/nat>

Does anyone know why this is not working?

Cheers,
J

use quotes

/ip/firewall/nat print where out-interface="ether1"