look under the "made in TW"
It's not an acceptable result for a prime. However this lens performs well under well controlled light (no "high-contrasting" zones).
CA is coming form refraction in high contrasting areas.
However, keep in mind that Canon 50mm at 1.4, 35mm at 1.4 (L), 85mm at 1.2 (L) do not show any CA on high contrasting elements!
Stopping down solves the problem for sure, then no point to get a 1.8. I bought a 1.8 because I need to shot at 1.8?