FP calculation bug within tabularray

Question

Strange results had been reported here when using the fp package inside a table using tabu package.

A solution had been proposed to manage the fact that computations are done twice by performing a test on \write parameter.

As it comes to do similar calculations with tabularray I get odd results as well, despite the test. Any idea to fix this? Here is a minimal example based on the topic I refer to:

\documentclass[11pt]{report}
\usepackage{fp} 
\usepackage{tabu,longtable}
\usepackage{tabularray}
\FPset\totalone{0}
\FPset\totaltwo{0}
\let\origwrite\write
\def\add#1{%
\relax\ifx\origwrite\write
  \FPadd\0\totalone{#1}
  \global\let\totalone\0
  \FPadd\0\totaltwo{#1}

  \global\let\totaltwo\0
\fi
  #1
}
\def\ptotalone{%
  \totalone
  \FPset\0{0}\global\let\totalone\0
}
\def\ptotaltwo{%
  \totaltwo
  \FPset\0{0}\global\let\totaltwo\0
}
\begin{document}
\subsection*{With longtabu:}
\begin{longtabu}{c}
    \add{0.25} \
    \add{0.5}  \
    \add{1}    \
    total one: \ptotalone
\end{longtabu}
total two: \ptotaltwo
\subsection*{With tabularray:}
\begin{tblr}{c}
    \add{0.25} \
    \add{0.5}  \
    \add{1}    \
    total one: \ptotalone
\end{tblr}
total two: \ptotaltwo
\end{document}

Thanks.