Zoom level is set per observation, intentionally by the system depending on the method of uploading, so as far as I can tell, there isn’t a bug here.
If you have a proposed change, please check existing topics to see if they cover your request and fill out the form in that category if they do not.
eg see https://forum.inaturalist.org/t/set-the-default-google-maps-zoom-level-for-observations/6827
https://forum.inaturalist.org/t/maintain-map-zoom-level-when-creating-observations/8195
https://forum.inaturalist.org/t/add-adjustment-of-default-zoom-level-in-explore/15065