In community server
Used bloodbag with matching blood type and it killed my character
Same server
Friend had bloodbag taken from his character with known blood type, next time he logged on blood type in bag was different to his character (no death, no mix up)
Had this exact same thing happen to me on a private vanilla server. I thought maybe I had to first use the alcohol tincture to disinfect the IV Kit? I know for an absolute fact it was the same blood type as mine because I was the only one on the server and had taken my own blood to act as an emergency transfusion for myself.