Hi Jeff Ranck (JRanck)"),
Thank you for reaching out Microsoft Community. We're sorry for the inconvenience this has caused you.
When you say, "the SD card randomly ejects itself, is this literally getting ejected from the SD card slot or just being unmounted and keeps displaying that it is ready to be ejected? This could be a compatibility issue. To initially assist you on this, it would be best if you can check this link https://support.microsoft.com/en-us/help/4495650/surface-what-sd-cards-are-compatible [https://support.microsoft.com/en-us/help/4495650/surface-what-sd-cards-are-compatible](https://support.microsoft.com/en-us/help/4495650/surface-what-sd-cards-are-compatible) so you would know what a Micro-SD card should be capable to make it work on your Surface device.
If this helps, feel free to mark this post as an answer. Otherwise, don't hesitate to respond to this thread if you need further assistance.
Kind Regards,
Crest_Z