[rebber]\begin{array]{l r} breaks the latex

[artragis]

When we parse some math operation into latex, the \ may be removed

input

$$
\begin{array}{l r}
  & 45 \\
+ & 218 \\
+ & 800 \\
\hline
= & 1063
\end{array}
$$

Actual result

\[ begin{array}{l r}
  & 45   
+ & 218   
+ & 800  \
\hline
= & 1063
\end{array} \]

Expected result

\[ 
\begin{array}{l r}
  & 45  \\
+ & 218 \\  
+ & 800  \\
\hline
= & 1063
\end{array} \]

[gilcot]

Also check if it's the case with \left and \right

[artragis]

it is possibly related,
we can also note that the \\ to say "line return" are not well parsed.

I also made some tests with other environments and got good parsing for

\begin{matrix}
   a & b \\
   c & d
\end{matrix}

this bug is really strange

[StaloneLab]

Fixed in version 11.1.0, thanks for the report @gilcot