MikroTik RouterOS 6.47.10
> /ip firewall filter
> disable numbers=19,20 ; print
...
19 X chain=input action=accept
20 X chain=forward action=accept
...
> enable numbers=20,19 ; print
...
19 I chain=input action=accept
20 chain=forward action=accept
...
> enable numbers=19,20 ; print
...
19 chain=input action=accept
20 chain=forward action=accept
...
Watch the ‘I’, meaning “Invalid”. It depends on the order of the numbers…
Ie. there is a programming bug in RouterOS b/c it depends on which number comes first in the command list: “20,19” causes the bug, but not “19,20”.