Created attachment 116509 [details]
Comparison between Konsole and Terminator, rendering color emojis.

SUMMARY
Some issue with color emoji rendering on GTK applications are happening. Two other old (but updated) installations of KDE Neon are rendering with no problem color emojis. But in a recent and fresh install, it's not possible to see emojis only on GTK applications.

STEPS TO REPRODUCE
1. Fresh install KDE Neon;
2. Install Terminator;
3. Copy a color emoji from somewhere and paste it on Konsole and Terminator.

OBSERVED RESULT
The color emoji are rendered on Konsole, but not on Terminator.

EXPECTED RESULT
Color emoji are rendered equally on KDE and GTK applications.

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: Neon
(available in About System)
KDE Plasma Version: 5.14.3
KDE Frameworks Version: 5.52.0
Qt Version: 5.11.2

ADDITIONAL INFORMATION
I had a similar issue between KDE and GTK applications on the previous installation of KDE Neon: accentuated characters like "é", "ó" or "ã" was only working on GTK apps, not on KDE apps.