Problems with assembling printed parts

Hello everyone,

I would like to build a large circle from four printed quarters. Unfortunately, three of the quarters always fit together perfectly, but as soon as I add the fourth quarter, there is a slit in the centre (see photos) and I have no idea why this is the case. Can anyone here perhaps help me? That would be great!

I am using an Ender-5 S1 from 2023 together with the Creality Slicer.

Thank you very much!

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