Filled zones of different nets merge into single filled zone

[Lenwo]

I have several filles zones on the bottom layer for thermal dissipation of LEDs. These zones are connected to the cathode pad of the LEDs on front layer by vias (leds without thermal pads). When trying to add a GND pour to the bottom layer the whole layer is being poured without respect to the existing thermal dissipation pours.

Here are some helpful images:

[Album] imgur.com

Adding GND pour to bottom layer:

As you can see the bottom layer is filled completely shorting the existing zones.

Same happens when I add a VCC and GND pour to front layer and press ‘B’ to refill all zones.

Background:
As you might tell from the schematic I am very inexperienced creating circuits and layouts. I am fairly sure this behaviour is either user error or a fundamental misunderstanding of the applied concepts.

Also I am not quite sure if the vias as I created them make any sense.

If this is a common problem I could have solved easily using the search function I am very sorry - I have used the search function and searched on google quite a while before I came here.

Further Information:
Used Version: KiCad 5.1.6-1

Thanks very much in advance!

[eelik]

If you have overlapping zones of different nets you have to make sure they have different priorities (in zone properties). More about zones: How to create a power plane (using zones).

[Lenwo]

Well that works, thank you very much.
I had tried that but created the GND plane after changing the priorities of the other zones. This way I did not notice the newly created GND zone also had the new priority. I assumed newly created zones always have priority 0.

Thank you, great help, easy solution!