Network/Connectivity Device randomly switches preferred SIM for mobile data.

  1. RicoBrassers
    Froyo May 29, 2019

    RicoBrassers , May 29, 2019 :
    Hey there,

    recently I got myself a second SIM card from another provider, primarily for data usage.
    SIM 1 is my primary SIM card with my primary phone number, etc.

    Configured default SIM in settings:
    Calling: Always ask
    Messaging/SMS: SIM 1
    Mobile Data: SIM 2

    Working like a charm. But sometimes, the OS changes the configured SIM for mobile data back to SIM 1 and I don't know why. I have to manually go back to the SIM settings and select SIM 2 for mobile data again.

    Just for clarification: This should NOT happen. If someone uses a SIM as SIM 1, that charges money per MB of data used, this could generate unexpected bills for the phone user, if the phone randomly switches preferred SIM for mobile data usage from SIM 2 to SIM 1. (Luckily, I don't have to pay per MB, but it's still annoying, especially since the connection speed of SIM 2 is usually much higher for me.)

    G_Known_as_P_vego likes this.
  2. G_Known_as_P_vego
    Cupcake Jun 5, 2019

    G_Known_as_P_vego , Jun 5, 2019 :
    Same issue, Formating phone did not solve the issue.
    I wonder how Oneplus can explain random changes in phone settings.

  3. mrdandouglas
    Froyo Jun 17, 2019

  4. Markysparky
    Cupcake Jun 17, 2019

  5. gezovicgr
    Cupcake Jun 18, 2019

  6. L1568809607288
    Cupcake Sep 18, 2019

    L1568809607288 , Sep 18, 2019 :
    My 6t is also doing this and it makes having two SIMs completely pointless because I have to manually open the phone and switch them around when I move between countries. I think what happens is whenever the phone is restarted it defaults to SIM1 for data, even if SIM2 is the preferred selection.

    Has anyone found any solutions to this?