Maybe initially update your statistics so we know how many hives you have.
Possibilities...
1)They are thinking of swarming perhaps and she has gone off lay prior to that journey
2) Queen is dead and they have made cells to replace her.
3) she is poor queen and they are wanting to replace.
Hard to assess but with sitings of cells it sounds like preswarm. Are they capped cells??
If capped I would split that colony to make them think they have swarmed. Look for the queen again. If present, put her in one hive with about 5 frames from the other hive. Leave 2 good queen cells in the original hive, with loads of stores on the remaining frames.
Put the hive with the queen back on original site and the capped cells hive on another area nearby.
Queenless, just split into 2 hives with 2 cells in each and equal frames also. Fill spaces with new frames.
Just re read, and realise not charged cells. Doh! So as above, keep close watch.
If developing do as above.