Changing one shape attribute auto. changes others

[wondunk]

Hello,

I've been enjoying Affinity Designer professionally for quite some time.
I often use it for character designs and end up having many copies of the same shape.
Sometimes I need to make a change to one of those shapes. Recently, what I noticed is, that when I 
make a change to one particular shape, it applies the changes to all the other shapes:

In this picture above you cann see that all six shapes have the same attributes. Stroke, fill color etc.

Then I changed the fill color to shape on the far left and it changed the fill color of ALL shapes automatically, as shown above.

Here is the thing:
I DO NOT have these shapes in Studio / Symbols, meaning I don't have them linked in any sort of way. Maybe I'm missing some simple basic toggle option, that allows me to disconnect these links.
Also infuriating is the fact, that when I perform an UNDO, it just un-does the changes to the far left shape and ALL OTHERS are left in the new state (in this case fill color: white).

I would greatly, greatly appreciate your help, as sometimes I end up manually reversing all changes, which can take hours when you have large canvases and countless artboards with the same shapes. 

Thank you!

[MEB]

Hi wondunk,
Welcome to Affinity Forums
Do you mind attaching the .afdesign file you used for your sample above so we can try reproduce the issue ourselves here? Are you able to reproduce this behaviour in a new document?