You are attempting to write at 5k speeds. That is a lot of data for any card. The more the data input, the more the heat. The more the heat, the more the possibility of failure to R/W adequately. Just because the camera is 5k capable, does not necessarily mean your equipment can maintain that speed. The card, possibly, may not be able to handle that higher speed at constant input. I would recommend searching, specifically, for a Micro SD card with speeds of 5k R/W specifically stated. There really is a lot more data difference between 4K and 5k. Billions more choices of color input! Ok for standard video/photo, but not good enough (same as 4K) for higher res slo-mo (60fps ok-but R/W rates much faster with high speeds can’t keep up!) Your bird could get very hot and possibly shut down. I recommend staying at 2.7k for faster speeds. It will still get warm, but should be within safety zone. Try your 5k down at 24/30 fps only. 4K up to 60fps and 2.7k to infinity and beyond. Try that and check the heat differences.
Let us know the outcomes.