I work as a journalist. Sometimes articles are omitted before important characters in headlines (such as the Karen and the customer in this headline) because it helps readers understand who's involved a little quicker than they otherwise would have done. These important words stand out a little more when they're not buried between articles and prepositions. Some editors also like to cut words from the start of headlines while leaving the same words in at the end because this allows readers to start easily and build up reading momentum, going from shorter phrases to longer ones.

Good observation haha. Basically, articles are often omitted in the headlines but it is down to the preference of the editor basically. But you're right, it is inconsistent in this headline and there isn't a clear reason why/a clear rule :)