1/2 Fractions can't be displayed in the same position as [Arial Unicode MS] while changing fonts to Kanji.
Solution
Each font has different character height, width, spacing and line spacing, hence this is designed behavior.
The same behavior can be seen in Microsoft word or outlook. See below examples:
Calibri font: ½
Arial font: ½
Notes and References
9698325
Hardware/Software Configuration
Platform: INTL64
OS: windows
OS Version: 1064
Product: NX
Application: DRAFTING
Version: V1872
Function: TABLES
Ref: 002-8146549