3.8.2 Pixhawk 1 I2C OLED corrupted display

On a Pixhawk 1, loaded with Plane 3.8.2, and an i2c connected OLED display, the first column of the display is corrupted.

The same Pixhawk 1 running copter displays with no problems.
Second display tried on Pixhawk 1 and the same corrupted first column appears.
The same 2 displays tried on Pixhawk 2.1 the display has no problems on plane 3.8.2.

So this seems to be Pixhawk 1 specific.

On a Pixhawk 1, loaded with Plane 3.8.2, and an i2c connected OLED display,
the first column of the display is corrupted.

Was firmware the only thin gthatc changed between runs? No extra
sensors on the i2c bus between Plane and Copter?

This was observed in bench testing.

The Pixhawk1 was wired up with sensors as shown.

Initially copter was loaded and all worked as expected but with no changes, nothing unplugged or plugged in, and plane installed, the display showed the corrupted 1st column.