these can be Zigbee channels; see the channel plan of ZigBee versus WiFi:
Do you see this everywhere in this building and as continuous signals? They now look continuous for the 10s span you have. As there is nothing finished in the building, I can imagine that these devices are looking for the right channel and are in a sort of scanning mode.
They have a coexistence mechanism to limit normally the used channels to the ones in red in the drawing once they notice WiFi signals so with AP deployed, it should sort itself out.
I haven’t seen this signature with Wifi present but it might of course be another source like Bluetooth beacons but those should also sort out once WiFi is present. It looks too ‘perfect’ to be random interference of electro engines or so. the good news then is that someone should know what they deployed