I suspect that input filtering is being done on ALL the variables at the moment of initialization now, and that an IPv6 address containing colons `:` is being wiped from the server array. This would explain no IP address being returned back to the client.(c)
It seems that WHMCS has problems using Whitelists/API restrictions. It can’t digest IPv6 addresses. Pity, as IPv6 are next door and hosting industry is quite sensible for this issue.
Some might argue on the fact that IPv6 is not here yet, but the standard of IPv6 addressing has been here for ages, and it’s not that hard to implement one. At least for the future.