For uno minima, when configuring GPIO with pinMode() function, there is a bug when configured using OUTPUT_OPENDRAIN PinMode.
The fix would be:
Replace line R_IOPORT_PinCfg(NULL, g_pin_cfg[pin].pin, IOPORT_CFG_PORT_DIRECTION_OUTPUT | IOPORT_CFG_PMOS_ENABLE);
with R_IOPORT_PinCfg(NULL, g_pin_cfg[pin].pin, IOPORT_CFG_PORT_DIRECTION_OUTPUT | IOPORT_CFG_NMOS_ENABLE);
This is my first arduino project, so I'm not sure how the bug reporting works. If someone can help point me to the proper way to report this bug, that would be appreciated.
In order to make all relevant information available to any who are interested in this subject, I'll share a link to @steveny530's report in the GitHub issue tracker: