I think its been said before, but its not a bug per se, but perhaps a poorly designed implementation of how your flights are recorded. I can post plenty of screenshots of my logbook showing things like 4 take-offs, and 4 landings. The difference is I interact with ATC, and go through the stages of flight as the sim expects. If you take off but the sim thinks you should be taxiing, it won’t progress to the next phase of your flight, and the take off will not be logged.
Don’t get me wrong, I do sometimes get take-offs missed, usually at uncontrolled airports. Landings are harder to miss, but I have noticed that when doing a touch, and go for example, if you don’t reduce your speed enough it won’t log the landing. You can tell when it logs as you typically get that little progress spinner at the bottom right of your screen. I found that out the hard way when I was aiming to get achievement for visiting 500 airports. If you land, then take off immediately it doesn’t count, you have to slow down. I don’t remember exactly but I think its around 15kts.
If you bring up the Objectives window from the top menu, that will tell you where the sim thinks the phase of your flight currently is. I’ve had some cases where I have taken off, and the Objectives window has something like “Prepare to land at destination airport”. Consequently that take-off did not log. If I could be bothered, to fix that I would need to declare I wanted to land at that airport again, taxi off the runway then announce I was clear, then announce taxi, and take-off once more, all the while keeping an eye on the Objectives window so I know what the sim expects of me.
If found a post where I tried to catch as many possible states your flight is in, from startup, taxi, takeoff, landing, and taxi to parking. Even then I think I missed one or two as they sometimes only appear on screen for a few seconds.