I am getting this issue while running a performance test.
The suggestions is to run it in incognito, but I am running it in incognito and still getting this issue.
It is still running the test and giving me a score, but it seems something is affecting.
There were issues affecting this run of Lighthouse: There may be stored data affecting loading performance in this location: IndexedDB. Audit this page in an incognito window to prevent those resources from affecting your scores.
i face the very same issue:
site data showed some amount of data in indexdb although indexdb itself appears empty when i investigate it by clicking the node. after clearing site data indexdb went to 0 ad everything appears cleared. the alert remains unchanged.
when running lighthouse in incognito mode the alert is not there, so that hint at least works fine on my machine.
I managed to clear this message by going in to the "Application" tab in Inspector and clicking "Clear site data" and then rerunning the Lighthouse test.
EDIT: spoke too soon... It seemed to clear it the first time and then the 2nd time I tried to re-run the test I got the same warning message. Perhaps it's not clearing everything?
