CATIA V5 Fillet Anomaly - Works on STEP, Fails on CATPart

I've come across an unusual issue both in CATIA V5 as well as in 3D Experience CATIA where the Fillet feature works fine on a STEP file but fails on the same geometry when using a CATPart. I’m trying to understand why this happens since the sketches are fully defined.

 

Here is the video regarding the problem in CATIA V5 

https://youtu.be/eST60D3jCIw

And this is within 3D Experience CATIA

https://youtu.be/pjItCt7vzuY

Has anyone in the community experienced this issue before? I'd love to hear your insights!

I have also uploaded the Stp file for this, there are no gaps between the two extruded elements and they are within the same PartBody Part Design