Lightning bolt under-voltage warning keeps appearing on Raspberry Pi 4 despite 5V 3A supply

Under-voltage warning behavior

I am trying to understand the exact trigger and logging behavior of the Raspberry Pi under-voltage indicator. My understanding is that the firmware shows the yellow lightning bolt when measured voltage on the 5 V rail drops below roughly 4.65 V, and that sustained under-voltage also triggers CPU throttling.

What I am trying to determine

Assume a Raspberry Pi 4 running a recent Raspberry Pi OS, powered through the USB-C port. The goal is to distinguish between a genuinely inadequate power supply and transient voltage dips caused by cable resistance or peripheral load spikes (e.g., USB devices drawing current during activity).

The uncertainty is how the warning is recorded and cleared: whether the firmware exposes a latched "under-voltage has occurred since boot" state versus a live "currently under-voltage" state, and whether throttling history can be correlated with those flags after the fact.

Questions

• Does vcgencmd get_throttled reliably distinguish a current under-voltage condition from one that occurred earlier since boot, and are those bit meanings stable across Pi 4 firmware versions?
• Is there a documented threshold hysteresis, so the bolt does not flicker when voltage hovers near 4.65 V?
• Can transient dips short enough to escape the on-screen icon still set the throttled/under-voltage flags?