Nov 29 21:31:21 dpinger WAN_DHCP 99.233.16.1: Alarm latency 19857us stddev 24963us loss 22%
Dunno, but 20+% packet loss is considered a down connection with dpinger default settings. You are having real issues with your ISP, it's not something that pfSense would be inventing. So yeah, disabling GW monitoring won't help obviously, the packets will still get lost and things won't work.