Opnsense box stops getting wan IP after 15 or 20 days

[meazz1]

I am running 21.1.6.
I have experienced twice in last month an a half that my router stopped receiving IPV4 WAN address from the AT&T pass thru modem. It does not lose the IPV6 address.
I had to reboot to get it back up and running.

What could cause this?
For troubleshooting this, what logs should I be looking into? I have Zenarmor- Sensei setup for LAN interface, and this is what I saw in the System Diagnostic Activity. Can this be the reason, "HeapDumpOnOutOfMemoryError"?
My box has 8 GIG of memory and Intel core i5 2.30 GHZ 4 core cpu.

• /usr/local/openjdk8/bin/java -Xms2g -Xmx2g -XX:+UseConcMarkSweepGC -XX:CMSInitiatingOccupancyFraction=75 -XX:+UseCMSInitiatingOccupancyOnly -XX:+AlwaysPreTouch -server -Xss1m -Djava.awt.headless=true -Dfile.encoding=UTF-8 -Djna.nosys=true -Djdk.io.permissionsUseCanonicalPath=true -Dio.netty.noUnsafe=true -Dio.netty.noKeySetOptimization=true -Dio.netty.recycler.maxCapacityPerThread=0 -Dlog4j.shutdownHookEnabled=false -Dlog4j2.disable.jmx=true -Dlog4j.skipJansi=true -XX:+HeapDumpOnOutOfMemoryError -Des.path.home=/usr/local/lib/elasticsearch -cp /usr/local/lib/elasticsearch/lib/* org.elasticsearch.bootstrap.Elasticsearch -d --pidfile=/var/run/elasticsearch/elasticsearch.pid -Epath.conf=/usr/local/etc/elasticsearch{VM Periodic Task Th}

[meazz1]

I wanted to move this to Zenarmor thread but did not know how, so I created a dup of this in that thread.