VLC has become the default app for pdf files

[CliffP]

I am running Windows 10 and VLC 2.2.8. Recently whenever I generate a pdf file VLC opens as the default program for the pdf file. I've checked the default apps for pdf files and it's set for Acrobat, I even reset it once but no help there. I tried the reset and setup applications buttons with no result. The latter just refers me back to the Windows default app which hasn't worked. This has just happened in the last few days and prior to that it worked just fine.

Thanks for help.