For some reason; used to indicate that something has happened or is the case although the reason is unclear.
どういうわけか彼は約束の時間に現れなかった。
For some reason he didn't show up at the appointment time.
パソコンが、どういうわけか何度も再起動する。
For some reason the computer keeps restarting.
どういうわけか試験の点数が前回より上がっていた。
For some reason my exam score was higher than last time.
どういうわけか会場にはほとんど人が来なかった。
For some reason hardly anyone came to the venue.