Takagi's name in Japanese

[TML]

I have noticed that Takagi's name in Japanese is not always depicted in a consistent manner. For example, in episode 401, when Takagi shows his badge, we see his name given as "高木 渉" (with his given name in Kanji), but in other episodes (for example, episodes 146 & 535), we see it given as "高木 ワタル" (with his given name in Katakana). Can anyone explain this discrepancy to me?

[Scar Akai]

I have noticed that Takagi's name in Japanese is not always depicted in a consistent manner. For example, in episode 401, when Takagi shows his badge, we see his name given as "高木 渉" (with his given name in Kanji), but in other episodes (for example, episodes 146 & 535), we see it given as "高木 ワタル" (with his given name in Katakana). Can anyone explain this discrepancy to me?

Maybe the editors screw up...

[Misaki-chan]

Maybe the animators forgot what kanji they used and also which episode they used it in, so they decided to use katakana...