This is the worst behavior. Just spent an hour tearing my hair out trying to figure out why all my power supply rails were shorted together after adding a couple LDO symbols... :
How can I stop kicad implicitly connecting nets connected to pins with the same name (e.g. VCC) - Schematic - KiCad.info Forums
The Mystery of the Missing Power Pins in KiCad | Details | Hackaday.io