I used pdfjs to split the pdf files, then add some watermark(the watermark string contains some Chinese). Finally, generate a new pdf file for browsing. Strangely, some of the text appears incomplete.What's happening?

--------libs version as follows: pdfjs: 2.16.105 pdf-lib: 1.17.1 vue: 2.6.10
Somebody said: "The CMap is compressed by Webpack". I put it in static resource directory, then the problem still exists. What do I need to do to fix it? thx