It would help if you showed how it looks in the slicer.
But from the photo it looks like it made the bridge in a circular way instead of in parallel lines. If you can make the bridging go strictly in parallel lines from top to bottom, it should turn out better.
It’s kind of crazy that slicers still attempt to make something like curved bridges.
I had a 300mm long part with a 10mm wide slit in it along the length of it, no matter what I did (bridge setting or part orientation), the slicer insisted to create the bridges for that slit parallel to the long direction, attempting a 300mm unsupported bridge, instead of orthogonal so it was only 10mm bridges.
I would go back to your CAD model and tweak it for better printability. If it was a model you downloaded and without a source CAD model I would just remodel it myself to be more printable.
Sometimes even layer height can affect bridge behaviour.
But first thing I’d do is to rotate the piece by 90° on the bed and see if the thin bridges that you can see behind the thick curved ones, change their orientation to be short instead of long.
And then try to figure out what makes those thick curved bridges happen.
It would help if you showed how it looks in the slicer.
But from the photo it looks like it made the bridge in a circular way instead of in parallel lines. If you can make the bridging go strictly in parallel lines from top to bottom, it should turn out better.
It’s kind of crazy that slicers still attempt to make something like curved bridges.
I had a 300mm long part with a 10mm wide slit in it along the length of it, no matter what I did (bridge setting or part orientation), the slicer insisted to create the bridges for that slit parallel to the long direction, attempting a 300mm unsupported bridge, instead of orthogonal so it was only 10mm bridges.
I would go back to your CAD model and tweak it for better printability. If it was a model you downloaded and without a source CAD model I would just remodel it myself to be more printable.
It looks to me like that’s not a flat area. That’s why it’s not using parallel lines. If you want good bridging it must be flat.
This is the answer.
Alternatively, use supports.
See if you can change the number of bottom layers or the bottom layer pattern to get a different result.
Honestly, I just keep changing all sorts of bridge related and unrelated settings until it does what I want. Maybe the piece lends itself to being printed on the head or on it’s edge (45° tilt) like this: https://www.reddit.com/r/3Dprinting/comments/mhcvut/pro_tip_if_youve_got_a_complex_part_youd_like_to/
Sometimes even layer height can affect bridge behaviour.
But first thing I’d do is to rotate the piece by 90° on the bed and see if the thin bridges that you can see behind the thick curved ones, change their orientation to be short instead of long.
And then try to figure out what makes those thick curved bridges happen.