I have the same exact problem. Did you ever find a solution?

I think it's only in GPU mode. If you choose "view using CPU" it disappears. Can this issue be fixed in GPU mode? Kind of annoying and CPU mode is way too slow for me.

I am having the same issue, I have checked on colleagues computers (Illustrator 26.0.0.1, all Macs, on Big Sur and Monterey), the only computer here that it is fine is on Big Sur and Illustrator 24.2.1.

This keeps happening today
everytime I have a curve it becomes this (see image)
first I thought it was just my blending shape not right but then I noticed it happens with just any curves, outlines, shapes, as long as it's a curve it creates extra shapes on top of it.

Hi guys. I have been having the same issue. I just exported the artboard as a pdf to see what would happen. The PDF appears fine, so seems to be a visual bug. Annoying though, so would be great if it got sorted.

I see this on 2021 version of Ai, but not 2020. The 2021 version in CPU mode is almost unusable even with basic files.

Images for reference.

When viewing in GPU view, there appears to be weird lines and shapes outside of what was drawn with the pen tool. The attached images of a shape at 50% opacity show how these inconsistencies in the shape appear and disappear when toggling between GPU and CPU. It seems this is only when there's a curved line, and does not appear when the shape is made up of straight lines only.

I can't actually use Illustrator for delivering an identity project! That's nuts.

same here. totally unacceptable.

Same thing. This is disgusting. The tool is not fit for purpose. Who can I speak to at Adobe to get them to finalise the identity project I'm working on? Need it by close of play today.

I am having this same issue on my 2020 iMac - I tried the previous of illustrator with the same files and appears fine, the older app just seems to crash my system.

iMac (Retina 5K, 27-inch, 2020) - 3.8 GHz 8-Core Intel Core i7 - AMD Radeon Pro 5500 XT 8 GB

I wonder if it has any relation to the issue I have in the same version of AI where sharp points aren't sharp in non-cpu preview mode.

I am using Mac OS 10.15.7 with Illustrator Version 25.3.1

When creating shapes with the pathfinder or shapebuilder, there is a problem with rendering where curved and straight shapes intersect. I have tried multiple files, updated Illustrator, and even opened old files to discover that the rendering issue is there on files that were made ages ago without issue... so the problem is not with the tools, but with how these shapes are rendering.
It's totally frustrating because precision work is impossible at the moment!

I do occasionally use snap to grid, but have tried with and without it. I have ensured that snap to pixel is off, as this causes other issues.

For this example, I've intersected a circle and square to create sharp corners. The results are consistently problematic.

I've added a video showing the problem as it occurs after creating the shape with both the pathfinder (divide) and shape builder tools. I then duplicate and rotate the shapes to show the issue is with rendering.

screenshots of
1. the overlapping shapes
2. I used the pathfinder to divide.
3. I show the problematic rendering up close
4. I show that there is no abnormality in the wireframe view.

To further test the issue, I made a couple of copies and rotated them. The screenshots here show

1. that the rendering issue changes depending upon rotation and
2. again there are no issues in the wireframe view

When creating shapes with the pathfinder or shapebuilder, there is a problem with rendering where curved and straight shapes intersect. I have tried multiple files, updated Illustrator, and even opened old files to discover that the rendering issue is there on files that were made ages ago without issue... so the problem is not with the tools, but with how these shapes are rendering. It's totally frustrating because precision work is impossible at the moment!

I do use snap to grid, but have tried with and without it. I have ensured that snap to pixel is off, as this causes other issues.

For this example I've intersected a circle and square to create sharp corners. The results are consistently problematic.

I've added screenshots of
1. the overlapping shapes
2. I used the pathfinder to divide.
3. I show the problematic rendering up close
4. I show that there is no abnormality in the wireframe view.

To further test the issue, I made a couple of copies and rotated them. The screenshots here show

1. that the rendering issue changes depending upon rotation and
2. again there are no issues in the wireframe view

I want to add that I mostly work with pathfinders when I create complex shapes. I already reported another bug with the "merge" pathfinder last summer (when path is too complex and you work with corners, some other unexpected behaviours pop up).

I am seeing the same. Here is a sample file and screenshot. I'm on an intel iMacPro running Big Sur.

Just checked my MacBook Pro, which is about a year old now, the system is up to date, the version is the latest for Illustrator, and the issue is also there.

Thanks.

It seems that on my new iMac (M1 silicon chip) both versions of Ai, latest, and Beta have a similar bug when it comes to some illustration corner, and it clearly shows this is linked to the handles of curves (these shapes were created with shapes and pathfinder), as when you pull these handles around, the bug moves / disappears.

What's expected is that the shape be seamless, perfect on the outside of it.

What happens: the shape has a weird artefact outside in the corner.

This makes illustrations imprecise, with artefacts.
Can you please look into this ? I have tried to work around this unsuccessfully.

My OS: Mac OS 11.4
Versions of Illustrator: latest + Beta
Computer: iMac M1

It seems that on my new iMac (M1 silicon chip) both versions of Ai, latest, and Beta have a similar bug when it comes to some illustration corner, and it clearly shows this is linked to the handles of curves (these shapes were created with shapes and pathfinder), as when you pull these handles around, the bug moves / disappears.

What's expected is that the shape be seamless, perfect on the outside of it.

What happens: the shape has a weird artefact outside in the corner.

This makes illustrations imprecise, with artefacts.
Can you please look into this ? I have tried to work around this unsuccessfully.

My OS: Mac OS 11.4
Versions of Illustrator: latest + Beta
Computer: iMac M1