Likely a beginner's misnomer.
Or maybe not. I saw 2 queen cells at the bottom of a frame of a package I hived April 9. One of the cells contained a developing larva. The purpose of my inspection was to check if 80% of the frames had been filled with comb, eggs, capped and uncapped larvae, and stores -- they had been. I also saw the queen.
Based on my own observations and theories developing from what I have read, a single developing queen cell is not cause for "immediate action."
Perhaps the bees were getting crowded and are "thinking" about swarming: I added a second box to give additional space to raise brood and place stores. This is my first guess.
Perhaps the bees want to replace the queen: I will check in a week or so to see how the second box is developing and the status of the queen cell. If I again find a good brood pattern and expansion I will leave the cell and check again in another week or so. In other words, now that I have seen the larva in the cell I will monitor the hive for changes, but I will leave the cell intact. I figure the bees put it there for a reason unbeknownst to me but my own reasoning and curiosity considers it a learning experience.
Best of luck with your bees. I hope others chime in as I am only a second-year beekeeper and still trying to learn.