The SIGLENT SDM series of multimeters has a Power On Last function that recalls the last instrument configuration settings used previous to a power cycle. For example, if you have the meter in ACV mode with fixed range, and power cycle the instrument, it will power on in ACV mode with fixed range.
The instrument does not instantly “save” these settings. They can take up-to 1 minute to be stored.
So, to ensure that the instrument powers on with the last settings used, wait 1 minute after any changes before powering the instrument off.