Hi Dan, confirming that the css below does fix this issue in Safari 8, as linked in https://moodle.org/mod/forum/discuss.php?d=277360#p1193793
/* set up the keyframes */
@-webkit-keyframes nodeInserted {
from { opacity: 0.99; }
to { opacity: 1; }
}
/* force a repaint with a super short duration */
#scorm_content > iframe
{
-webkit-animation-duration: 0.001s;
-webkit-animation-name: nodeInserted;
}