Troubles with Timestamp in Constant read with SEN-14066

Hi collegues! i mounted a SEN-14066 with an antenna on a RedBoard and it works pretty fine but…

My goal is obtain the elapsed time from pulse T0 to the tag receive data T1 in continuous read mode but I have some troubles with the timestamp variable in the array of data because it seems to reset counter every second. I don’t understand the behaviour of this variable.

is it normal?

Is there any way (if need, i can modify the arduino library) to calculate this elapsed time or is there a way to know how this variable works?

Is there a way to activate phase parameter on M6E nano?

thank you so much.