This KB provides information related to the support for Next-term functionality for firewall filter in ACX series routers.

Next-term functionality for firewall filter in ACX series routers not supported.

Below is the link in which the same is documented under Nonterminating Actions (ACX Series Routers)

https://www.juniper.net/documentation/us/en/software/junos/routing-policy/topics/topic-map/firewall-filter-match-conditions-and-actions-acx.html