Enabling 'Enable Gesture Recognizer' resolves this
Axis Event mapped to pinch no longer returns values.
Working in 4.19
Confirmed on Android + iOS
Confirmed in MAIN 4.23 @ CL 4961509
Result: Print string is 0
Expected: PrintString Returns value of 1 when fingers remain where they started pressing and value decreases as fingers get closer and increases as fingers move apart.
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-70163 in the post.