This looks like nisen bokeh: an out-of-focus rendering where blur disks become bright-edged rings, which makes lines and edges look doubled or harsh instead of smoothly blurred.

It’s a lens characteristic, not a camera fault. It tends to appear only in a certain range of defocus, and foreground and background blur can look different. In your examples, the distracting areas are slightly out of focus near close-focus distances, where this effect can become noticeable.

You usually can’t “fix” it in-camera, but you can often avoid or reduce it by changing the shot:

• change focus distance a little
• use more or less defocus
• alter your composition so busy foreground/background areas aren’t in that transition zone
• try a different focal length or a different lens if smoother bokeh matters

So the main cause is the way your lens renders out-of-focus detail, especially close up—not incorrect settings or technique.