I'm with Andrey.
Pedals turning when you walk the bike may be a problem, but there's a very real possibility that it's meaningless.
This is about friction. Freehweels have internal friction and "want" to turn with the wheel. At the same time, the chain, RD pulleys, and BB have friction and want to stand still. So it's a question of balance, sometimes not so much about which has higher friction, as which has lower.
On my road bike, the balance is so perfect, that the pedals turn when in high gear, but not in low. They are also more likely to turn when the chain is newly oiled, than later.
The acid test isn't whether the pedals turn, but whether there's enough freewheel friction to slacken the upper loop more than very slightly when coasting.
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