I can think of 2 possible

I can think of 2 possible scenarios:

     Scenario 1:  Your SD card may have some corrupted sectors, in which case it's time to replace the SD card.

     Scenario 2:  The card may not be fast enough for the data rate at which your camera is trying to record.  I have seen this before, where because of the speed of the card, the camera can sometimes record video to it, but it is unstable and often causes the camera to crash.

     Either way, it sounds like it's time to replace the card.