I have the same experience in 4.25.2 - It turns off the post-process AO and within I did not find any way to activate it again. r.AmbientOcclusionLevels can’t activate it either. AO is visible on buffer but would be nice to see some options for it in the future.
Little question aside: Is there a way to tell SSGI to be active and rendering even if the camera is not looking at it? I have the big issue that it turns off on items once they are just slightly out of the cameras bound and within the whole effect is for cats.