Hi, I have an update for this. I was having a problem that seemed to be related to the timing of the signal.

In my setup I use a Teensy 3.2 and the OctoWS2811 library, but the outputs of the Teensy are connected to a MAX485 transmitter and received by a MAX485 on the strip side. It seemed that the MAX485 modifies slightly the duration of the pulses, and the timing resulted a little distorted on the output of the receiver. What I found out through testing (because I don't have an oscilloscope at hand) is that modifying the lines for T0H and T1H in OctoWS2811.cpp resolved this issue.

My settings are:
#define WS2811_TIMING_T0H  70
#define WS2811_TIMING_T1H  150
It works flawlessly now. I'm working with WS2812B strips bought on AliExpress.