When creating a bug report, adding a new checkbox which asks "Bug already reported to Niantic Support" will hopefully limit the bug reports that are only posted to the site but not to Niantic. Additionally, a modal that appears when someone didn't report to NIA already could remind them explicitly that the site tracker is not run by NIA, that only reporting it here won't bring it to Niantics attention and that admins may report the bug on their behalf.
When creating a bug report, adding a new checkbox which asks "Bug already reported to Niantic Support" will hopefully limit the bug reports that are only posted to the site but not to Niantic. Additionally, a modal that appears when someone didn't report to NIA already could remind them explicitly that the site tracker is not run by NIA, that only reporting it here won't bring it to Niantics attention and that admins may report the bug on their behalf.