r - confidence interval shading disappears in certain programs when saved as pdf -

i using ggplot (version 3.2.5) line graph geom_line. confidence interval use geom_smooth. save plot with

ggsave("name.pdf", width=8, height=6, dpi=300)

i run os x el capitan , word 2016. if copy graph word 2016 on mac grey shading of cofidence interval can seen.

the problem when open same graph on windows in word or powerpoint grey shading disappears.

any suggestions problem highly appreciated. thought .pdf should same no matter programm gets used.