Chartjs-Chart JS version 3 not showing in pdf for engine wkhtmltopdf

I am also facing similar issue with chartjs radar chart in pdfkit = 1.0.0 to generate PDFs,
as of my understanding pdfkit is using wkhtmltopdf engine in background. wkhtmltopdf uses css2 which has lot of incompatibility issue with chartjs or newly developed chart libs.

Experienced the same issue with another pdf tool (hiqpdf) it seems the engine these tools use support JavaScript/jquery versions the same as Internet explorer 11 does. When you check your page in IE11 you probably see syntax errors related to chart.js because chart.js doesn’t support ie11 anymore they seemed to have used syntax that can’t be used in pdf render tools.. I struggled with this the whole week and finally chose to use the 2.9 version of chart.js using the v3 migration guid backwards… with 2.9 everything seems to work fine in combination with pdf generation tools, so probably the fastest solution for you?