This is one of the causes of the SD Card failing to Insert/Reject on Sony A7 Series of cameras.
Jump to @5:50 for solution.
SD Card I've used is the new Sandisk Extreme 150MBps/s https://amzn.to/2F5jsHj
Affordable External Battery Pack https://amzn.to/2VQadjR
Sony A7 III https://amzn.to/2NXjpQD