If A Line Contains CJK Character Will Forced On Unicode Font

If A Line Contains CJK Character Will Forced On Unicode Font.
I Take A Photos In Under,You Can See The Result Of If A Line Contains CJK Characters And English Characters

How To Reproduce
Type some CJK Characters And Some English Characters And Make Sure They Are in A Same Line

Observed Result
It Will Forced On Unicode Font

Expected Result.
It Will Not Forced On Unicode Font