"01/01/1970" appears in the reports / statistics (version 0.0.7.3)

"01/01/1970" appears in the reports/statistics of the version 0.0.7.3

This date appears every time between two correct dates.

20/10/2015 | 01/01/1970 | 21/10/2015 | 01/01/1970 | 22/10/2015...