Hong Kong English Accent?

I know someone who has lived in Hong Kong all their life(though their family is from the Philippines), and they have an interesting English accent. When I first heard them speak, I thought they were American. My question is, why do they have a rhotic accent, and not use received pronunciation? Is this actually common in Hong Kong?

The way Mandarin Chinese pronounces r-sounds, I think that could be one reason...

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