To repoduce the problem I've created a VM with 3 network cards and installed Rocky Linux 9.2 minimal.

My IP addresses are:
- IP1 192.168.122.80 used for apache
- IP2 192.168.122.186 used for jboss node 1
- IP3 192.168.122.235 used for jboss node 2

After first boot:
- dnf update
- dnf install httpd mod_proxy_cluster java-1.8.0-openjdk-devel
- in /etc/sysconfig/selinux change SELINUX=permissive
- firewall-cmd --permanent --add-rich-rule='rule family="ipv4" source address="IP1/24" accept'
- reboot

Configure httpd
- put httpd.conf in /etc/httpd/conf
- in /etc/httpd/conf/httpd.conf change lines 2 and 3 (Listen) and lines 75 and 93 (VirtualHost) with your IP1 [don't change ports]
- mv /etc/httpd/mod_proxy_cluster.conf.sample /etc/httpd/conf.modules.d/10-cluster.conf
- in /etc/httpd/conf.modules.d/00-proxy.conf comment line 8 #LoadModule proxy_balancer_module modules/mod_proxy_balancer.so

Download JBoss EAP 6.3 and unzip in two directories (node1 and node2)

Configure JBoss node1
- put standalone.conf in ~/node1/bin and change line 50 THISIP=192.168.122.186 with your IP2
- put standalone.xml in ~/node1/standalone/configuration and change line 433 proxy-list="192.168.122.80:81" with your IP1 [don't change port]
- put jboss-helloworld.war in ~/node1/standalone/deployments/
- touch ~/node1/standalone/deployments/jboss-helloworld.war.dodeploy

Configure JBoss node2
- put standalone.conf in ~/node2/bin and change line 50 THISIP=192.168.122.186 with your IP3
- put standalone.xml in ~/node2/standalone/configuration and change line 433 proxy-list="192.168.122.80:81" with your IP1 [don't change port]
- put jboss-helloworld.war in ~/node2/standalone/deployments/
- touch ~/node2/standalone/deployments/jboss-helloworld.war.dodeploy

Start services:
- systemctl start httpd
- ~/node1/bin/standalone.sh
- ~/node2/bin/standalone.sh

Checks:
- apache is running http://IP1/server-status
- cluster is running http://IP1/cluster-status (see cluster-status.png)
- application is running on node1 http://IP2:8080/jboss-helloworld
- application is running on node2 http://IP3:8080/jboss-helloworld
- no error messages in /var/log/httpd/cluster_error_log

Test application on cluster http://IP1/jboss-helloworld
HTTP status 503 service unavailable
For each request a error i written in /var/log/httpd/error_log
[Tue Aug 29 17:47:41.978206 2023] [:error] [pid 17034:tid 17077] proxy: CLUSTER: (balancer://cluster). All workers are in error state