play up

Reader's Digest 5月号 @Work, Funny moments from the officeの記事、Light bulb momentに面白い表現がありました。
Our lights were playing up, so we called an electrician. Our eight-year-old grandson was fascinated by this man, and sat observing his work very closely. Noticing his interest, the electrician said, "You can ask me anything, son."
After thinking quietly for a few moments, our grandson said, "How fast can giraffe run?"
"play" が含まれているので "lights were playing up" は蛍光灯が悪くなりかけてちらついている印象を受けますがどうでしょう？　play up" の意味を辞書で確認します。
・Cambridge English Dictionary: If a machine plays up, it does not work as it should.: The starter motor was playing up again.
・Collins English Dictionary:
(tr) to emphasize or highlight ⇒ to play up one's best features: British informal to behave irritatingly (towards) (intr) British informal (of a machine, car, etc) to function erratically ⇒ the car is playing up again: British informal to hurt; give (one) pain or trouble ⇒ my back's playing me up again: It was a miracle that my prostate did not play up , which was my greatest concern.
やはりニュアンスとしては完全に機械が駄目になった時よりも、調子が悪くなって来たときに使う様ですね。