Ok, I tested this on a document that didn't contain any Hebrew and it still happens, like jarlaxl lamat wrote in his comment. Also, unchecking the PDF/A-1 option prevents this problem for me too.
So the exact bug is:
Arabic numerals when exporting to PDF with PDF/A-1 enabled, a Writer document that contains a table pasted from Calc. Only if Calc _is still open_ when the export is being done.
Ok, I tested this on a document that didn't contain any Hebrew and it still happens, like jarlaxl lamat wrote in his comment. Also, unchecking the PDF/A-1 option prevents this problem for me too.
So the exact bug is:
Arabic numerals when exporting to PDF with PDF/A-1 enabled, a Writer document that contains a table pasted from Calc. Only if Calc _is still open_ when the export is being done.