I synchronized two event cameras and tested them. When recording, pictures of the master and the slave camera are perfectly fine and no lag is displayed. But when I open raw files, master.raw is fine, slave.raw shows obvious lag (similar to slow motion), average event rate is around 40 kev/s while the average event rate of master.raw is around 8 Mev/s. Furthermore, when I open these two files with showcase, two videos are synchronized again and no lag (slow motion) is shown. What would possibly be the problem?