PROBLEM
Vector shapes are distorted or snapped to a grid when exported to PDF.
For example, this is how the feature looks in ArcMap Layout, zoomed in at approximately 3000%:
This is how the same feature looks in the exported 300dpi PDF at 3200%:
This most likely occurs when viewing the PDF at a high zoom percentage. For example, 1000% or higher. This happens with PDFs generated from any application.
Even when exporting a pure vector map to PDF, do not expect the vectors to maintain perfect geometry when zooming in to a percentage much greater than the output resolution.
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