I get a very weird "error" just momentarily when I compile my document but when the compilation is finished it disappears and I have no errors or warnings. As you can see the "error" is huge and it keep going as there is a scrolling bar. This started happening the time that I used the \usepackage{steinmetz} and its command \phase{}. If I delete them then everything is ok. Why is this happenning and how can I fix it?
A MWE which has that problem when compiled:
\documentclass[12pt]{article}
\usepackage[top=0.7in, bottom=1.2in, left=0.8in, right=0.8in]{geometry}
\setlength{\parindent}{0cm}
\usepackage{xltxtra}
\usepackage{xgreek}
\setmainfont[Mapping=tex-text]{GFSArtemisia.otf}
\setsansfont[Mapping=tex-text]{GFSArtemisia.otf}
\setmainfont[
Ligatures=TeX,
Extension=.otf,
UprightFont=*,
BoldFont=*Bold,
ItalicFont=*It,
BoldItalicFont=*BoldIt,
]{GFSArtemisia}
\usepackage[fleqn]{amsmath}
\usepackage{unicode-math}
\usepackage{steinmetz}
\everymath{\displaystyle}
\newcommand{\3}{\vspace{0.3cm}}
\newcommand{\1}{\vspace{1cm}}
\newcommand{\rr}
{
\hrule
\vspace{0.3cm}
}
\begin{document}
$Y=|Y|\cdot e^{j\phi}=|Y|\phase{\phi}$
\end{document}

I don't know if this helps but these are the settings of my Texmaker:

After using the solution proposed by Ulrike Fischer all this "scary" warning disappears and in its place appears the following. It is of the same nature which means that it appears during compilation and disappears after the compilation is complete. What is that?

p2e-xetex.defis loaded. Tested with TeX Live 2014, 2013 and 2012. – egreg Sep 12 '14 at 21:43pict2ehas been added in 2009, see the file in TeX Live – egreg Sep 12 '14 at 21:45\everymath{\displaystyle}is not recommendable. – egreg Sep 12 '14 at 21:54\everymath{\displaystyle}. I get that picture too as I said after the compile there is no errors. The errors exist only during compilation for a very short time. – Adam Sep 12 '14 at 22:18\phasesymbol if you removesteinmetz. – egreg Sep 12 '14 at 22:46