When attempting to add a network, followed by pressing the SAVE button, or when attempting to delete more than 1 network (Firewall Networks tab), the following error is thrown:
Array to string conversion
Numbers other than 17 have appeared, but 17 is the most common error in the red popup banner. As a side note - very hard to cut and paste those errors as the banner goes away very quickly.
Comment: It seems that recent updates affected Firewall behavior as relates to parsing the network list. On restarts/reloads the full list does not seem to fully populate into iptables. Have been unable to isolate specific examples other than to say working systems were broken due to Firewall after recent updates. Turning off Firewall confirmed source of issue. Removing all networks from trusted via a script and reloading fixed issue. Perhaps investigation of this issue and others reported (FREPBX-19644, FREEPBX-19646) will identify the problem which seems to relate to processing long network lists.