Flat, non-faithfully flat, submodule of a faithfully flat module

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Let $R$ be a unital ring (not necessarily commutative) and let $M$ be a (left) faithfully flat module over $R$. Can there exist a non-zero flat (left) $R$-submodule of $M$ that is not faithfully flat.

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Let $A$ be any faithfully flat module and $B$ be any flat module that is not faithfully flat. Then $M=A\oplus B$ is faithfully flat and contains $B$ as a submodule.