I noticed that frequently some of my best (or at least some of my "interesting") sectors happen on my "in" laps. By "in" lap I mean a lap where I start at full pace, but then in the middle of the lap they start waving the checkered flag and I proceed back to the pits.
They are accounted for in the "Opt lap" row of the summary, but are not shown anywhere else in the table, making it confusing. It took me a few track days to understand that. One of my friends who recently started using RaceChrono also expressed confusion when we reviewed their data.
From the technical standpoint, an "in lap" can be defined as a continuous sequence of checkpoints triggered after the last complete lap, but without triggering the start/finish line again (e.g. due to the geometry of the paddock and where the virtual start/finish line is located). At least in my case, an "in lap" is always followed by stopping the session. I guess there can be something like a checkbox asking "do you want to end the current lap?".