Apple pencil

I too am having issues with my Apple Pencil on the classic whiteboard but not one that I am seeing here,  My issue is that when I use my apple pencil to write as I write the letters disappear immediately(but not all of them!) and sometimes I have to write the same letter(symbol) three or four times before it stays on the screen.  But there is even more weirdness going on,  If I use the highlighter feature available as a pencil choice it works as it should.  In addition if in the pencil mode and I use my finger to write, there is also no issue with letters disappearing.  HELP!!!!