Problems when highlighting or underlining text

[Philippe22667283l4af]

Hello,
For the past few days, when I annotate .pdf files (I highlight or underline words or sentences), it happens that the WHOLE DOCUMENT is highlighted (or underlined), which makes all my previous highlighting (or underlining) work useless.
I do Apple+Z to undo this but there is no way to go back!
Does anyone have a solution?
Philippe