You have exceeded the maximum files submission for your SRX platform size: This statement is correct because file scanning on SRX300 Series device has a limit on the number of files that can be submitted per minute based on the platform size3. For example, SRX320 has a limit of 10 files per minute3.

https://www.juniper.net/documentation/en_US/junos/topics/topic-map/security-idp-policies- overview.html

SRX chassis clustering supports active/passive and active/active for the data plane. In an active/active configuration, both cluster members process and forward traffic, which increases throughput and provides redundancy. For the control plane, SRX chassis clustering supports active/active, meaning that both cluster members can process and forward control traffic, providing redundancy and improved scalability