biblatex 导致随机字母出现在我的文本环境之外

Question

我很困惑，当我第一次向主文档添加引用时，一切都正常进行，但是在添加 1 或 2 个“构建和查看”之后，我的文本环境上方开始出现随机字母和数字。我很想得到帮助！

还应该注意的是，当我删除 \usepackage[backend=bibtex,style=chem-acs]{biblatex}讨厌的字母时它们就会消失，但是改变围兜样式和后端不会改变它们。

\documentclass{article}

\usepackage{auto-pst-pdf}
\usepackage{graphicx}
\usepackage{chemscheme}
\usepackage{lipsum}
\usepackage{chemnum}
\usepackage[backend=bibtex,style=chem-acs]{biblatex}
\usepackage{setspace}
\doublespacing
\addbibresource{introbib.bib}


\begin{document}

\section*{1.0 Introduction}

\subsection*{\textit{1.1 N-Heterocyclic Carbenes}}

N-heterocyclic carbenes (NHCs) have experienced a period of transformational growth in the field of organocatalysis, originating from the first successful isolation of a stable carbene in 1991.\autocite{ref1}


\printbibliography

\end{document}

和 .bib

@article{ref1,
  langid = {english},
  title = {A Stable Crystalline Carbene},
  volume = {113},
  issn = {0002-7863},
  url = {http://pubs.acs.org/doi/abs/10.1021/ja00001a054},
  doi = {10.1021/ja00001a054},
  number = {1},
  journaltitle = {J. Am. Chem. Soc.},
  urldate = {2019-01-16},
  date = {1991},
  pages = {361-363},
  author = {Arduengo, Anthony J. and Harlow, Richard L. and Kline, Michael},
  file = {C:\\Users\...\Arduengo et al. - 1991 - A stable crystalline carbene.pdf}
}