Conflit entre le package "chemformula" et "cellspace" ?
J'utilise cellspace pour avoir un espace vertical entre la ligne et mon texte. 
Quand j'utilise le package "chemformula" cet espace ne se crée plus.
NB : J'utilise la notation C{p{4cm}} car dans mon document j'ai besoin du package siunitx.
Est ce un conflit entre les deux packages?
Quelle est la solution ? 
Je travaille sur TeXStudio.
Voici un ECM : 
     \documentclass[english]{article}
    \usepackage{chemformula} %problem
    \usepackage{array}
    \usepackage{multirow}
    \usepackage{cellspace}
    \usepackage{siunitx}
    \usepackage{babel}
    
    \setlength{\cellspacetoplimit}{12pt}
    \setlength{\cellspacebottomlimit}{12pt}
    
    \begin{document}
    \begin{table}
      \centering
      \caption{Caption caption}
      \label{Bla bla}
      {\footnotesize
        \begin{tabular}{|C{p{4cm}}|C{p{5cm}}|C{p{3cm}}|}
          \hline
          Categories & Categories & Categories \\
          \hline
          \hline
          Blah blah & Blah blah & Blah blah \\
          \hline
        \end{tabular} }
    \end{table}
    \end{document}
Ici le fichier.log que j'obtiens (seulement la partie entre µfile list* et *****)
         article.cls    2014/09/29 v1.4h Standard LaTeX document class
      size10.clo    2014/09/29 v1.4h Standard LaTeX file (size option)
        chemformula.sty    2017/03/23 v4.15e typeset chemical compounds and reactions (
    CN)
           expl3.sty    2017/05/13 L3 programming layer (loader) 
         expl3-code.tex    2017/05/13 L3 programming layer 
         l3pdfmode.def    2017/03/18 v L3 Experimental driver: PDF mode
          xparse.sty    2017/05/13 L3 Experimental document command parser
         l3keys2e.sty    2017/05/13 LaTeX2e option processing using LaTeX3 keys
        tikz.sty    2015/08/07 v3.0.1a (rcs-revision 1.151)
         pgf.sty    2015/08/07 v3.0.1a (rcs-revision 1.15)
      pgfrcs.sty    2015/08/07 v3.0.1a (rcs-revision 1.31)
    everyshi.sty    2001/05/15 v3.00 EveryShipout Package (MS)
      pgfrcs.code.tex
     pgfcore.sty    2010/04/11 v3.0.1a (rcs-revision 1.7)
    graphicx.sty    2014/10/28 v1.0g Enhanced LaTeX Graphics (DPC,SPQR)
      keyval.sty    2014/10/28 v1.15 key=value parser (DPC)
    graphics.sty    2017/04/14 v1.1b Standard LaTeX Graphics (DPC,SPQR)
        trig.sty    2016/01/03 v1.10 sin cos tan (DPC)
    graphics.cfg    2016/06/04 v1.11 sample graphics configuration
      pdftex.def    2017/01/12 v0.06k Graphics/color for pdfTeX
    infwarerr.sty    2016/05/16 v1.4 Providing info/warning/error messages (HO)
     ltxcmds.sty    2016/05/16 v1.23 LaTeX kernel commands for general use (HO)
      pgfsys.sty    2014/07/09 v3.0.1a (rcs-revision 1.48)
      pgfsys.code.tex
    pgfsyssoftpath.code.tex    2013/09/09  (rcs-revision 1.9)
    pgfsysprotocol.code.tex    2006/10/16  (rcs-revision 1.4)
      xcolor.sty    2016/05/11 v2.12 LaTeX color extensions (UK)
       color.cfg    2016/01/02 v1.6 sample color configuration
     pgfcore.code.tex
    pgfcomp-version-0-65.sty    2007/07/03 v3.0.1a (rcs-revision 1.7)
    pgfcomp-version-1-18.sty    2007/07/23 v3.0.1a (rcs-revision 1.1)
      pgffor.sty    2013/12/13 v3.0.1a (rcs-revision 1.25)
     pgfkeys.sty    
     pgfkeys.code.tex
     pgfmath.sty    
     pgfmath.code.tex
      pgffor.code.tex
        tikz.code.tex
     amsmath.sty    2016/11/05 v2.16a AMS math features
     amstext.sty    2000/06/29 v2.01 AMS text
      amsgen.sty    1999/11/30 v2.0 generic functions
      amsbsy.sty    1999/11/29 v1.2d Bold Symbols
      amsopn.sty    2016/03/08 v2.02 operator names
       xfrac.sty    2017/05/13 L3 Experimental split-level fractions
    textcomp.sty    2017/04/05 v2.0i Standard LaTeX package
      ts1enc.def    2001/06/05 v3.0e (jk/car/fm) Standard LaTeX file
    xtemplate.sty    2017/05/13 L3 Experimental prototype document functions
    nicefrac.sty    1998/08/04 v0.9b Nice fractions
      ifthen.sty    2014/09/29 v1.1c Standard LaTeX ifthen package (DPC)
    scrlfile.sty    2017/04/13 v3.23 KOMA-Script package (loading files)
       array.sty    2016/10/06 v2.4d Tabular extension package (FMi)
    multirow.sty    2016/11/25 v2.2 Span multiple rows of a table
    cellspace.sty    2009/07/31 v1.6 Spacing table cells (JN)
        calc.sty    2014/10/28 v4.3 Infix arithmetic (KKT,FJ)
     siunitx.sty    2017/05/19 v2.7g A comprehensive (SI) units package
    translator.sty    2010/06/12 ver 1.10
    translator-language-mappings.tex
       babel.sty    2017/05/19 3.10 The Babel package
     english.ldf    2017/01/24 v3.3q English support from the babel system
      ts1cmr.fd    2014/09/29 v2.5h Standard LaTeX font definitions
    supp-pdf.mkii
    pdftexcmds.sty    2017/03/19 v0.25 Utility functions of pdfTeX for LuaTeX (HO)
    ifluatex.sty    2016/05/16 v1.4 Provides the ifluatex switch (HO)
       ifpdf.sty    2017/03/15 v3.2 Provides the ifpdf switch
    epstopdf-base.sty    2016/05/15 v2.6 Base part for package epstopdf
      grfext.sty    2016/05/16 v1.2 Manage graphics extensions (HO)
    kvdefinekeys.sty    2016/05/16 v1.4 Define keys (HO)
    kvoptions.sty    2016/05/16 v3.12 Key value format for package options (HO)
    kvsetkeys.sty    2016/05/16 v1.17 Key value parser (HO)
    etexcmds.sty    2016/05/16 v1.6 Avoid name clashes with e-TeX commands (HO)
    epstopdf-sys.cfg    2010/07/13 v1.3 Configuration of (r)epstopdf for TeX Live
    translator-basic-dictionary-English.dict    
    siunitx-abbreviations.cfg    2017/05/19 v2.7g siunitx: Abbreviated units