I'll tell you a funny story about myself: Last weekend, before a sports event, I tested the whole set with the Timy3 device at home in the living room.
TED2 synchronize the time via GPS automatically, and with Timy3 I synchronized the time manually according to the alarm clock (radio controll).
However, when I started sending test pulses to START and FINISH, the Msports Pro software failed to calculate the result. The start time from TED2 was fine, but the finish time from Timy3 showed a warning.
I researched this error for a long time. I looked for the error in the Timy3 settings as well as in the software settings. I tried different versions of the software and still nothing. I still couldn't figure out where the error happened and I was getting desperate.
After about an hour of experimenting, I finally realized where the mistake was.
In Europe we still use summer time and winter time. All technology with GPS must be corrected when the time changes (twice a year). The time has recently changed and I forgot to make a correction for TED2 (Timy3 were synchronized according to the alarm clock).
So the start was "an hour behind target" but I didn't register it at all as I was focused on the software warning. Only after the GPS time was corrected was everything OK and I could calm down.