mod_proxy_cluster crash when using BalancerMember

Hello,
I'm experiencing an issue very similar to https://issues.jboss.org/browse/MODCLUSTER-356
When I try to use a BalancerMember directive, I get a segmentation fault, caused at line https://github.com/modcluster/mod_cluster/blob/1.3.1.Final/native/mod_proxy_cluster/mod_proxy_cluster.c#L2223
I tried to remove directives from the virtual host, but the issue persists until there is at least one ProxyPass using a balancer defined with BalancerMember. I attach a .conf file where I put all of the configurations involved in the issue and which is causing the crash.

If I put a check at line 2223, there are no more segmentations, but a 503 caused by mod_proxy_cluster.c(2332): proxy: byrequests balancer FAILED

Thanks,
Paolo