Hello Tournesol,
Visual Studio kept breakpoint information in the user specific Solution.suo file. Can you delete it and have a test again?
If the issue still persist, please check if the symbol is loaded correct. You can verify it in Visual Studio by opening Debug -> Windows -> Modules
In the modules window, go to the assembly you are debugging, check its symbol status, check if it is user code. In the symbol file column, check if the file path is expected.
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