Error in Efficiently encode images and Serve images in next-gen formats

[DickyMacias]

I changed some of my pictures to webp in the website and everything worked fine, then a few days later, PSI showed an error in Efficiently encode images and Serve images in next-gen formats. I thought that was something regarding my changes and then run lighthouse and everything worked fine. I left a few days past and everything was OK in PSI, but when I made again some changes, PSI started to brought those errors back. For that reason I think that there is a bug or some issue with those metrics.

Also due PSI cannot read those metrics, it is showing a bad performance, that I cannot see if it is affecting the UX 28 days report.

Oh, I realized that this issue is only related to the mobile test.

Hope, someone can help me with.