A factor that could affect it: diffraction is so huge on these tiny sensors and cheap lenses may not be sharp, so it's possible that the image is not sharp enough for you to see chromatic aberration ! Chromatic aberration can only be seen if the image is otherwise clear.
I am far from certain that this is the only reason for this (it is possible that any chromatic aberration that exceeds diffraction and that other sources of non-sharpness are removed by algorithms sophisticated dealing with the raw data of the sensor). . But it can be a reason.
I think that the combination of lack of sharpness, due to diffraction, a lens and poor algorithms, can help explain everything you see.
Edit: @ DeltaOscarUniform has calculated that, unless the number of megapixels is excessive, the diffraction should be non-existent because of the relatively small F number F2.8 (typical). However, other sources of lack of sharpness prevail. However, a 12 megapixel phone camera still has half the pixels of a 24 megapixel / no-mirror DSLR, so the low megapixel could be a part of the explanation.