I had a look at those pictures on Imgur, but I do not see any “anomaly”.
Can you describe what you consider to be such an “anomaly”, and preferably mark it in one of the pictures with a circle or arrow or similar. (Hand drawn with the mouse and somewhat wavy lines is best, as it is then clear it’s not made by CAD software).
At the moment my best guess is that you expected the edge of a zone to be straight because you drew a straight line, but KiCad does much more than that. It calculates distances between objects, and retracts the edges of zones to conform to clearance rules.
If you are refering to these bumps in the zone outline:
They are perfectly normal.
Look at the pads next to them. The very thin red lines are a visualisation of the clearance area around the pads and can be turned of with Pcbnew / Preferences / Preferences / Pcbnew / Display Options / Clearance Outlines / Do not Show
The bumps in the GND plane itself follows the outline of the clearances of the combined pads.
Also note the area near the bottom of this screenshot.There are no pads there, and therefore the zone does not have to be made narrower to conform to clearance rules and it follows the boundaries you drew.
If you mean something completely different, then explain better, and indeed attaching the zipped project itself makes diagnosing “anomalies” a lot easier.