I am making the sort of rhetorical parallel between Oberth effect that I conclude applies even to light because light is actually solid of some sort photons or gravity well of Earth/Sun/galaxy, black holes effect. If I am making any sense. Oberth effect may cause space-time distortions.
Can the Oberth effect cause space-time distortions?
No, but the mass(es) used for the maneuver might.
Note that the velocity of the spacecraft performing the maneuver might cause a slowing of it's time relative to an observer, but:
- At anything less than extreme speeds (a significant percent of the speed of light) it would be almost immeasurable.
- As far as I understand, time dilation due to a relative velocity is not, technically, part of a space-time distortion - which is due to gravitational effects.