Streaming Media Player: OLED Weirdness

Of late, the OLED displays on two RPi 3 streaming players (the others are RPi 2) have occasionally gone blank, while the players continue to work fine. I checked the logs, swapped MicroSD cards, rebuilt the images, and generally screwed around, all to no avail. The SH1106 controller has a command containing a single bit to blank the display and, perhaps, an SPI data transfer error could shut it off.

This is much harder to explain:

Mirror-image OLED display
Mirror-image OLED display

There’s a hardware command to flip the display top-to-bottom, not left-to-right. The Luma OLED driver can rotate the display in 90° increments, but AFAICT not reflect it.

Yes, they’re networked, but, no, they’re not directly exposed to the Intertubes.

Changing streams had no effect. Shutting down and rebooting restored normal operation.

There’s been exactly one such failure so far, so I lack evidence.

I have no clue what’s going on.