Huh, somehow I glossed over the part where a regular neutron star would have bursts from <1s to 60s, while this body has bursts between 30 and 300 seconds. So i

Huh, somehow I glossed over the part where a regular neutron star would have bursts from <1s to 60s, while this body has bursts between 30 and 300 seconds. So it's still a different phenomenon than known pulsars. But I don't think it covers the core of what I meant to suggest/ask: if the object is spinning around 2 axes (for whatever reason) rather than one, that could still be an explanation why the observed periodicity from Earth does not match what we expect its actual rotation period to be.