分かんない。

我也不清楚。

Beats me.

バグだか何だか分かんないけど、このソフトはちゃんと動かない。

tbd

I dunno if it's a bug or what, but this software doesn't work right.

I don't know if it's a bug or not, but this software doesn't work correctly.

I don't know if it's a bug or what, but this software doesn't work right.