Esri World Hillshade layer with linear burn blend mode causes rasterization of map

[ErikBreedon]

Why would a PDF export as image, even when I have Output as image unchecked? Pro 3.4.3. I noticed this is not happening with a similar 8 1/2" x 11" layout. I'm going to test some other paper sizes, but it's definitely happening for D paper. EDIT: See comments below; issue was isolated to Esri World Hillshade when displayed with linear burn blend mode.

[ErikBreedon]

Edit: It is sometimes exporting parts of the layout as vector and others as raster. The layout has four maps. One map displays just fine. Some text elements in the layout are rasterized, some aren't. Ideally, nothing should be rasterized anywhere. I'm having difficulty finding the offending element of the map or layout that is causing this.

[ErikBreedon · Accepted solution]

I'm isolating this further. I was able to eventually find that Esri World Hillshade with linear burn blend mode was causing the entire map to rasterize, even though it was at the bottom of the map contents. Normal blend mode allowed the map to draw properly. 

I later found this documentation that notes which burn modes cause rasterization: https://pro.arcgis.com/en/pro-app/latest/help/mapping/layer-properties/apply-visual-effects.htm

I would expect it to rasterize below those layers, not the entire map.

Solution: Linear burn blend mode causes rasterization of entire map. Use multiply instead.