WIFI Firewall Fail - SOHO MkIII

Firmware v.8.1 SOHO. I’ve noted on previous firmware versions that the WIFI firewall feature does not work as expected. “Deny All Except…”
Entered MAC addresses of 2 cellphones, both Verizon Samsung. Only one phone will connect to WIFI, depending upon the MAC address order. Each MAC address is entered on a different line. Same symptom as with previous firmware versions. Can’t make any sense of it.