Jason, when did you purchase the camera? Can you post the firmware version it is at? Can you post the batch number (the format is 0813, 1013, etc.) I ask because the GoPro H3+ Black had some very significant focus issues when it first came out but later production runs have been reported to be much better.
Also, can you post the model number of the SanDisk memory card? There are pretty tight requirements for cards that properly take full resolution data and the model number will allow a purchaser to know that.