Learn Romanian: Din păcate, a intervenit o problemă.

The phrase literally translates to "from sin" or "out of pity" (from the noun păcat). Here, it functions as a discourse marker, meaning it expresses your attitude about the entire situation rather than just describing the action of the verb. Because it sets the tone for the whole thought, it sits at the very beginning of the sentence and is set off by a comma.

Why is the verb a intervenit placed before the subject o problemă?

In English, we almost always say "Subject + Verb" (A problem came up). In Romanian, verbs that express existence, appearance, or occurrence (like a interveni, a apărea, or a se întâmpla) frequently come before the subject, especially when introducing new information. While O problemă a intervenit is strictly correct, putting the verb first sounds much more natural to a native ear.

I learned that a interveni means "to intervene." Why is it translated as "came up" here?

You are correct that a interveni means "to intervene" when a person steps into a conflict or situation. However, when the subject is an abstract complication or event (like o problemă or o situație), its meaning shifts to "to arise", "to occur", or "to come up".

Could I use din nefericire instead of din păcate to mean "unfortunately"?