I was identifying unknowns when I came across an observation where the observer’s observation count displayed as zero:
While I was in the identify portal when I found it, “zero observations” also shows up on the observation’s page (https://www.inaturalist.org/observations/13659754) and on the user’s profile page (https://www.inaturalist.org/people/vladnet). From all three locations, if I click the link on the “0 observations”, the resulting display in Explore mode shows the observer’s one observation. As far as I can tell, there’s nothing weird about the observation besides the fact that it’s not being counted.