I've also run into this problem with the High Priest outside of Poko Kohara. Killed him in a bunch of different ways and dragged him around to different places on the map just to check, happened each time.
savegame: https://drive.google.com/open?id=1JgViP_M3Tf3GxoxLTMgzw7nDBR60_QJO
output_log.txt
DxDiag.txt
output_log.txt
output_log.txt
output_log.txt