Contains the meaning of "Although some bad situation has been avoided, but it can't be careless", similar forms also include "~からよかったものの", such as
"あなたがたまたま確認してくれたからよかったものの、もう少しで原稿の締め切りに間に合わなくなるところだった"
(fortunately you happened to help me confirm it, otherwise it would be almost It's too late for the submission date.)
Examples:
- この大事な資料が見つかったからいいようなものの、万が一、紛失したらどうするんだ。It's okay because I found this important material, but what if I lose it?
- 火事にならなかったからいいようなものの、これからたばこの火の始末に注意してください。Fortunately, no fire broke out, and attention should be paid to extinguishing cigarette butts from now on.
- 今回は事故が起こらなかったからいいようなものの、これからよく注意しないといけないですね。This time it's okay because there was no accident, but I have to be careful from now on.