Using the 32x32 matrix with an STM32F405 Feather Express, I'm observing a number of flickering and misplaced LEDs, which distort the edges of the image. This appears to occur more on one side of the matrix than the other.

Test script. This exact same script, when used on a Feather M4 Express with the same matrix (jumpers still used and only connections re-arranged) does not cause this issue.

This behavior also with Circuitpython built at the original STM32 RGBMatrix PR (#2831), so it may be specific to this screen size, since @jepler did not report any problems like this in his PR.

Any additional testing to confirm this issue would be appreciated! I've checked it with two separate feathers and two separate LED Matrixes of this size, but I do not have any other sizes to check against.

Sorry for lousy image quality, my phone camera really isn't catching this issue well. The "wrong" pixels are a lot more apparent to the naked eye. Attempted text is "++++"