Artifacts with scrolling text

1

I’m running 3 daisy-chained 16x32 rgb matrices (adafruit) on a Raspberry Pi 4. Scrolling text is working well except for some artifacts in the pixels to the left of the characters. It’s not too bad with a single color r,g, or b but gets worse with multiple colors, especially white. To scroll the text I’m doing a os.system call to the scrolling-text-example with the following flags:

sudo ./scrolling-text-example --led-rows=16 --led-chain=3 --led-slowdown-gpio=2 -l 1 -s 5 -f <font path> -C <color>  <text>

EDIT: forgot to say I’m using the deprecated wiring scheme “classic-pi1” because I initially followed teh old Adafruit tutorial to wire it up, to be able to use that wiring I had to create a new mapping in /lib/hardware-mapping.c. So could my wiring potentially be the issue?
So I’ve tested different values for led-slowdown-gpio and 2 is the best one. This is a speech-to-text-to-translation application so I’m using a USB mic, Python SpeechRecognition library, and calls to google speech-to-text and translate-shell for text translation, so reading through the troubleshooting tips for this library I suspect the SpeechRecognition.listen() call could be causing the static output on the display.
Here are a couple video examples:
red
white
If anyone has tips on how to further troubleshoot I would appreciate input!

2

Further testing, nevermind the application I’m running it from, the artifacts continue to appear when I run scrolling-text-example straight from the command line, with a little bit on single colors and more with multiple colors. Here’s what I’m using in the function call:

sudo ./scrolling-text-example --led-rows=16 --led-chain=3 --led-slowdown-gpio=2 -s 5 -f ../fonts/9x15.bdf -C 255,255,255 "How's it going?"
3

I’m going to bite the bullet and try redoing the wiring with the “regular” mapping.

4

I rewired it according to the “regular” mapping with no change.

5

Did you tried to change power supply? It could also be caused by cables that are too thin

6

Thank you for the suggestion. The power supply is 5V, 2100mA, seems like it should be sufficient. I have made a change in the code that appears to have minimized the effect due to making threading processes more efficient. Not completely gone but I think will be acceptable.