Why are my brackets with gaps and sometimes even knurled shape?
How can I solve this issue without having to draw the forms with another tool (Broken matrix - gaps in brackets (solved with Tikz))
Three examples of the problem are show on the figure below:

A MWE is below. When I change lscape with pdflscape the problem disapear. I use Adobe Reader XI on Windows 7 to see the pdf. On the viewer from texniccenter the problem do not appear
\documentclass{article}%
\usepackage{lscape}
\begin{document}
\begin{landscape}
First example:
\scriptsize
\begin{equation}
\left\{
\begin{array}{lcc}
C \\ \\
0 \\ \\
0 \\ \\
0 \\ \\
0 \\ \\
~~~~\vdots~~ \\ \\
0 \\ \\
0 \\ \\
0 \\ \\
0 \\ \\
0
\end{array}
\right.
\end{equation}
\end{landscape}
\newpage
\begin{landscape}
Second example:
\scriptsize
\begin{equation}
\left[
\begin{array}[pos]{ccccccccccccc}
C \\ \\
0 \\ \\
0 \\ \\
0 \\ \\
0 \\ \\
0 \\ \\
\vdots \\ \\
0 \\ \\
0 \\ \\
0 \\ \\
0 \\ \\
0 \\ \\
0
\end{array}
\right ] \newline \left[
\begin{array}[pos]{c}
U \\ \\
U \\ \\
U \\ \\
U \\ \\
U \\ \\
U \\ \\
\vdots \\ \\
U \\ \\
U \\ \\
U \\ \\
U \\ \\
U \\ \\
U \\ \\
\end{array}
\right ] = \left[
\begin{array}[pos]{c}
R \\ \\
R \\ \\
R \\ \\
R \\ \\
R \\ \\
R \\ \\
\vdots \\ \\
R \\ \\
R \\ \\
R \\ \\
R \\ \\
R \\ \\
R \\ \\
\end{array}
\right ]
\label{114}
\end{equation}
\end{landscape}
\end{document}