Flashing white light at the bottom of the circle

Two wired doorbell devices working for 2+ years went off-line with this flash code. No changes to my router; my other wifi devices continue to connect 20+ feet farther from my router. “Flashing white light at the bottom of the circle” is missing from Learning Light Patterns for Wired Doorbell Plus (formerly Video Doorbell Pro) and Ring Doorbell Flashing Light Patterns Guide. Ring needs to update their help pages to add missing info. The Ring app reconnect screens identify this flash code as “inadequate power supply”. If so, then the device issued this code erroneously. I measured the power connections at 26VAC, which is adequate. Pressing the side button failed to initiate the connection sequence. I disconnected power and reconnected power on both devices, no other actions. Both devices promptly reconnected to my wifi and became completely operational. Ring needs to communicate a workaround for their device malfunction.