I have only experienced the "unexpected instant maximum ramp down" issue while using Muggle mode.
Muggle mode is quite beneficial for those using the SP36 who are not familiar with Anduril so they do not end up in the Stobes, Blinkies or Lockout mode.
Also be aware that while the SP36 uses a USB-C charging port, it charges most reliably with a USB-A to USB-C cable. Some clarifying information is in this thread:
Post #10 by forum user Phlogiston in the above thread describes a USB-C to USB-C cable configuration that should also work.