OPNSense not able to re-claim memory space after killing multiple process

[Afif]

Hi,
I have a strange issue where memory fill up very quickly and then swap get running out of space error causing the system/router crashed. This has been happening since last year and I have to reboot every 2 days before my whole network down. I tried to reduce the RAM from 16G to 4G (I thought it was required more RAM but the issue still happening but it delays the system crashed up to 1 weeks) and add 2G to swap (enabled in settings). I also reduce the plugins and the issue is still there. I also tried to deploy from scratch and import the config but the issue still persist. I attached my system log and I don't have any clue what was causing this, So I need your advice/help on this. Thanks in advance.

Regards,
Afif