ec and its inputs look OK:
> [00:00:02] Loading MOVED for 
> /var/poudriere/data/.m/CURRENTamd64-default/ref/usr/ports
> [00:00:03] Gathering ports metadata
> [00:00:03] Warning: (ports-mgmt/poudriere-devel): jexec 
> CURRENTamd64-default jid=11 uid=0 euid=0
> [00:00:03] Warning: (misc/freebsd-release-manifests): jexec 
> CURRENTamd64-default jid=11 uid=0 euid=0
> [00:00:03] Warning: (misc/freebsd-release-manifests): jexec 
> jail_attach() errno=1
> [00:00:03] Warning: (misc/freebsd-release-manifests): jexec: 
> jail_attach(11): Operation not permitted
> [00:00:03] Warning: (ports-mgmt/pkg): jexec CURRENTamd64-default jid=11 
> uid=0 euid=0
> [00:00:03] Warning: (misc/freebsd-release-manifests): Error: Error 
> looking up dependencies for misc/freebsd-release-manifests
> [00:00:03] Warning: (ports-mgmt/pkg): jexec jail_attach() errno=1
> [00:00:03] Warning: (ports-mgmt/portconfig): jexec CURRENTamd64-default 
> jid=11 uid=0 euid=0
> [00:00:03] Warning: (ports-mgmt/pkg): jexec: jail_attach(11): Operation 
> not permitted
> [00:00:03] Warning: (ports-mgmt/portconfig): jexec jail_attach() errno=1
> [00:00:03] Warning: (ports-mgmt/portconfig): jexec: jail_attach(11): 
> Operation not permitted
> [00:00:03] Warning: (ports-mgmt/pkg): Error: Error looking up 
> dependencies for ports-mgmt/pkg
> [00:00:03] Warning: (ports-mgmt/portconfig): Error: Error looking up 
> dependencies for ports-mgmt/portconfig
> [00:00:03] Error: 
> /usr/local/share/poudriere/bulk.sh:gather_port_vars:184:Fatal errors 
> encountered gathering ports metadata
>
> but the call fo jail_attach() fails.

But does this also happen with 74bd6fb1eb028d15df407efb62628253dab90aa5? 
Have you tried a clean build?

The problem with the "too many open files" still exists. And now the main-weekly pkgbase is also affected.