With these stories, it is usually pretty obvious to me what the person did wrong. It is not always clear that they should have been denied, but it is often clear why they were denied (and my sympathy is therefore tempered).
In this case, the lack of details makes it hard to say. However, as you pointed out, she mentioned a "visa technicality."
She also says, "I further explained that my current work visa application had been complicated due to a filing mistake and that I had been waiting on a decision."
Generally, if you leave the country with an application outstanding, that application is considered abandoned. So, if I had to guess, it looks like she was attempting to enter the U.S. to live and work without a visa. Anybody surprised at the result?
+1 this. I've been on a student visa and several work visa's during my time in the USA, on each occasion it was made clear to me when I could and could not travel without risk of not being readmitted. It really feels like this person got into trouble due to something like this. Of course we can't say for sure because she provides no details in her account of what happened.
Not necessarily, she could have been applying to extend a H1B visa and still have a valid one to travel under. I'm sure there are other cases too, e.g. I was travelling with H1B while my green card was processing (and had two separate sets of re-entry paperwork).
In this case, the lack of details makes it hard to say. However, as you pointed out, she mentioned a "visa technicality."
She also says, "I further explained that my current work visa application had been complicated due to a filing mistake and that I had been waiting on a decision."
Generally, if you leave the country with an application outstanding, that application is considered abandoned. So, if I had to guess, it looks like she was attempting to enter the U.S. to live and work without a visa. Anybody surprised at the result?