can't diff embed bolt

[looping67]

const beforeA = {"ops":[{"insert":"新"},{"insert":{"DuoYinEmbed":{"character":"鲜","pinyinList":["xian1","xian3"]}}},{"insert":{"DuoYinEmbed":{"character":"的","pinyinList":["de5","di4","di2"]}}}]}

 const afterA = {"ops":[{"insert":"新"},{"insert":{"PreEmbed":{"text":"鲜","tagTxt":"xian1","ssml":{"tag":"phoneme","prop":"ph","value":"xian1"},"curBtnKey":"duoyin","ssmlValue":"xian1"}}},{"insert":{"DuoYinEmbed":{"character":"鲜","pinyinList":["xian1","xian3"]}}},{"insert":{"EndTagEmbed":{"curBtnKey":"duoyin"}}}]}

Object.stringify(new Delta(afterA).diff(new Delta(beforeA))

// output==>
{"ops":[{"retain":1},{"insert":{"DuoYinEmbed":{"character":"鲜","pinyinList":["xian1","xian3"]}}},{"insert":{"DuoYinEmbed":{"character":"的","pinyinList":["de5","di4","di2"]}}},{"delete":3}]}

there is no PreEmbed and endTagEmbed 。is it right?