A very short one…
I recently had problems with an ESP32 board resetting while developing a LoRa networked system using ebyte E22 modules. This was tracked down to a catastrophic drop – I mean a serious drop to <2V for several ms – in the voltage supplied to the ESP32 and, after some investigation, this was tracked down to the MIC5504 being used to drop a 3.7V nominal Lithium battery down to 3.3V. Replacing the LDO with a RT908033G35 fixed things and showed a clean oscilloscope trace. This wasn’t selected specifically to solve the issue, but had become my LDO of choice based on dropout voltage and current rating. It does have a better PSSR than the MIC5504 but I don’t think that, by itself, explains the dramatic difference in behaviour, so presume there was some nasty RF pickup in the MIC5504.
This happened with a completely separate transmitter nearby, with NO electrical connection. – ie it is not high frequency ripple (LDOs typically do not have good rejection at high freq), nor a transient.