If they truly lost the queen, those would be emergency cells but it's tough to know what's really going on with this colony having so little information. A queen has emerged from the cell in the first picture and in the second picture another queen cell is on day 15 or 16 with another queen ready to emerge from that cell (the tip of the cell is a giveaway to its age). They are going through the 30-day requeening process and it appears that they are on day 15 to 17 or 18 in the cycle. By day 25 they will be broodless and by day 28-30, there should be a laying queen if she mated and returned home successfully. When you see queen cells, you know something is happening to the colony. With enough info, you can usually figure out if they are going to swarm, or are replacing an underperforming queen, or they lost the queen and are making a new one.
What we don't know is if they swarmed, if they have health issues (that's not a lot of bees in those pics), or if they just aren't building very fast. When did you inspect? Was there a chance that the queen got killed during an inspection?
Take a look at the May 29 AMA #2 workshop. That workshop has pictures of various kinds of queen cells and covers the 30-day requeening calendar - what to expect on what days.
https://www.vermontbeekeepers.org/calendar/past-workshop-recordings