We are using ArcGIS Pro 2.8.3 and are seeing that cached basemaps are dropped (not captured) in any layout exported as a PDF (or JPEG or TIFF as well). Assuming it's related to how cached images draw, but wish we really knew why it was happening and if it could be fixed...
Are there any plans to address this in future patches? Or can anything be done to circumvent this glitch (besides not using cached basemaps...)
Catherine Hansen | MNIT Services partnering with MN Department of Natural Resources
Are you using a custom cache basemap? If so, you may want to check the following options in ArcGIS Server
Service Properties (Service Editor) -> Capabilities -> Mapping ->
Uncheck "Allow per request modification of layer order and symbology"
Hope this helps.