Adding header makes text unsearchable

[Silvia5C1D]

Adding header makes document text unsearchable by injecting random hidden spaces. The document text appears unaltered and prints okay, but pdf is unsearchable. Copy and paste reveals random hidden spaces that garbles the text by separating word characters with hidden encoding.

[Silvia5C1D]

This issue occures in documents printed to pdf from Google Docs. It doesn't seem to be an issue with scanned documents.

[Silvia0D4C]

Other viewer/editors (Evince/LibreDraw) are do not have this issue.