On my 2018 Pacifica, I am having difficulty keeping a pre-set station regardless of AM, FM, or Sirius. For example, let's say button 1 on AM is preset to 840 and I want to change it to 590. I hold the station down until the correct station appears in the first slot (just like you do with any car). Then after my van is turned off and restarted, the pre-set reverts back to the original 840. Sometimes it doesn't happen the very next time I start the car but the second or third time. So now I am having to constantly reset the station or retune as I drive. Any ideas?