Sometimes "check bit not equal to 1"

[Cen-XIN]

I ran the simple example described in "README.md" for several times. Sometimes it threw the exception "check bit not equal to 1". Sometimes it worked well. I don't know why...
Btw I use RPLidar A1 and connect it to a Raspberry Pi 3B.

[Cen-XIN]

In every 5 executions, there always are 4 times of "check bit not equal to 1" and 1 success. So weird :-)