When I was active online and when I was driving some config on my own host, I noticed that host doesn't updated my PB on LFSW when my ISP had problems with connection (~5% packet loss to master server).
Also when others ISP's had some problems with connection/routing this happened several times on public hosts.
I guess that problem is also with other stats i.e. number of laps, burned fuel, info about finished race etc.

So my idea is to add ability for host to retry updating stats in case where host doesn't receive confirmation of receipt from master server.

Hey, I had the exact same problem, once in my own host and once in a public server. Don't know if the reason in my case is the same as the one you stated though.