It's been more than a decade since I was involved with emergency services, but ~15 years ago there was a requirement (in Australia and elsewhere) that phones must be able to call emergency services from any available network even if the preferred carrier did not have service in that area. I assume that is still the case.
That requirement forces phones to have some degree of special handling for emergency calls. It may have required (or been interpreted to require) that a phone make emergency calls over 3G if VoLTE was unavailable. I can imagine someone deciding that means "lets just use 3G for all emergency calls" because who ever expected a case where 4G was available and 3G was not.
That requirement forces phones to have some degree of special handling for emergency calls. It may have required (or been interpreted to require) that a phone make emergency calls over 3G if VoLTE was unavailable. I can imagine someone deciding that means "lets just use 3G for all emergency calls" because who ever expected a case where 4G was available and 3G was not.