Labels overlap in ArcGIS Pro 2.3 and higher when using the Maplex Label Engine.

Solución alternativa

• Importing the map and sharing or exporting the layout in full extent.
• Copying and pasting in a new layout of the same dimensions (84.1 cm x 118.90 cm Portrait) gives no issues.
• The PDF named Layout is an export when the layers were added to a new layout with the mentioned settings and is simply importing the ArcMap document. The above is exported keeping 1000 dpi, Adaptive or JPEG without compressing the graphics and without embedding fonts. Attaching the PDF exported while testing the same in ArcGIS Pro 2.3 and 2.4.0-alpha.1+build.18982. 

Pasos para reproducir