It seems that exporting cells containing nonalphanumeric characters to SVG or PDF formats doesn't work as it should in Mma 12 on Linux (Fedora 30). For example
ImportString[ExportString[Cell["Why this? Test 1234!+=*", "Text"], "PDF"], "PDF"]
generates
Import::general: Unknown font type /CIDFontType0
and creates a garbled PDF file. With
Export["test.svg", Cell["Why this? Test 1234!+=*", "Text"]]
I equally get a weird-looking SVG file
All the tricks described here do not seem to make any difference.
Mmm 11.3 and older versions are not affected. I suppose that Windows and macOS versions of Mma 12 are also not affected, since that would come out much earlier, but I didn't check explicitly
Can someone confirm this behavior of Mma 12 on Linux?