My Bosch Washing Machine stops mid cycle with 2 red lights flashing?

Occasionally my Bosch WFD2061 stops mid cycle with two red lights flashing, when I re-press the start button it continues to end of progamme without any further problem.
While still under guarantee the engineer told me it was due to the filter being blocked, but the filter is clear and it continues to do this - so I just put up with it. Now having discovered this website I wonder if anyone else has this problem?