Why is Quantum software not showing all GNSS constellations being used with Apex5?

Depending on a users location it may be observed that when activated for Apex5 users may note that not all constellations appear to be in use:

APEX5 solution is capable of utilising satellites from 5 different constellations (GPS, GLONASS, Galileo, BeiDou and QZSS). However, there is a few factors which could cause a constellation to be excluded from the solution.

The system is designed to utilise satellites and constellations that provide the best solution possible. Most commonly it can be observed that QZSS is not included in the solution, as this is a regional constellation and users in regions such as Europe and Africa will likely observe this behaviour.