Could a spacecraft that uses a gravitational force engine cause time shifts as an unfortunate side effect?

By altering local gravitational fields to provide propulsion - would it cause timeshifts as a result? So if it was near the ground people may loose time, and if seen in the air, the craft may seem to move at incredible speeds or make impossible right angle manoeuvres? It could be normal movement and normal speeds... show more By altering local gravitational fields to provide propulsion - would it cause timeshifts as a result?

So if it was near the ground people may loose time, and if seen in the air, the craft may seem to move at incredible speeds or make impossible right angle manoeuvres?
It could be normal movement and normal speeds - but because of the time shift generated - it will look speeded up.
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