Migration from Python 3.7 to 3.9 gone bad

Hi guys, I’am in the process of upgrading my project from Python 3.7 to 3.9 but the Luma.oled library is spazzing out… In the attached picture you see a scrolling text. With 3.7 everything works fine but with Python 3.9 the scrolling text is completely broken. Minimal static examples all work.

RPI 3B+
5.4.79-v7+
Version: luma.oled 3.8.1 (luma.core 2.2.0)
Python3.9.1 completely fresh venv

Package                          Version
-------------------------------- ---------
Adafruit-Blinka                  5.9.1
adafruit-circuitpython-bme280    2.5.1
adafruit-circuitpython-bme680    3.3.0
adafruit-circuitpython-busdevice 5.0.1
Adafruit-GPIO                    1.0.3
Adafruit-PlatformDetect          2.23.0
Adafruit-PureIO                  1.1.8
cbor2                            5.2.0
certifi                          2020.12.5
chardet                          3.0.4
Cython                           0.29.21
dbus-python                      1.2.16
Deprecated                       1.2.10
idna                             2.10
luma.core                        2.2.0
luma.oled                        3.8.1
mock                             4.0.3
pi-ina219                        1.3.0
pi-rc522                         2.2.1
Pillow                           8.0.1
pip                              20.3.2
pycairo                          1.20.0
pyftdi                           0.52.0
PyGObject                        3.38.0
pyserial                         3.5
python-lirc                      1.2.3
python-mpv                       0.5.2
pyusb                            1.1.0
requests                         2.25.0
rpi-ws281x                       4.2.5
RPi.GPIO                         0.7.0
setuptools                       49.2.1
smbus2                           0.4.0
spidev                           3.5
sysv-ipc                         1.0.1
urllib3                          1.26.2
wheel                            0.36.2
wrapt                            1.12.1
xmltodict                        0.12.0

Expected behaviour

Scrolling text without artifacts. Code can be found here: https://github.com/majuss/wladio/blob/master/radio/display.py

Actual behaviour

Scrolling text with haevy glitches.

The runner example is also broken, if I don’t stretch it across the whole screen.

I will update this issue with my findings.

[majuss]

I use a SSD1322 and no same glitches with 7.1.2.

[majuss]

I switched to a Pi 4 and now everything works with Python3.9