Problemi con longtable

Buongiorno, ho un problemino con una longtable. Non so per quale motivo stano facendo i capricci le ultime due righe centrali della tabella in questione. In particolare, la multirow da 35 e da 27
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\begin{longtable}[h]{lccccc}
\hline
\multicolumn{6}{c
}{\textbf{Dimensioni longitudinali e trasversali dei \emph{Pit} per config. Z (\emph{$\mu$m})}} \\ \hline
\textbf{Conf.} & \textbf{X} & \textbf{Y} & \textbf{n° \emph{pit}} & \textbf{Media X} & \textbf{Media Y} \\
\hline
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\multicolumn{6}{c
}{\textbf{Dimensioni longitudinali e trasversali dei \emph{Pit} per config. Z (\emph{$\mu$m})}} \\ \hline
\textbf{Conf.} & \textbf{X} & \textbf{Y} & \textbf{n° \emph{pit}} & \textbf{Media X} & \textbf{Media Y} \\
\hline

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\multirow{6}{*}{\textbf{Z1}} & 14.25 & 16.19 & \multirow{6}{*}{6} & \multirow{6}{*}{38.62} & \multirow{6}{*}{11.93} \\
& 85.25 & 15.00 \\
& 12.31 & 10.15 \\
& 62.92 & 14.26 \\
& 54.80 & 9.34 \\
& 2.17 & 6.67 \\ \hline
\multirow{17}{*}{\textbf{Z2}} & 13.12 & 21.19 & \multirow{17}{*}{17} & \multirow{17}{*}{25.48} & \multirow{17}{*}{15.33} \\
& 20.52 & 11.37 \\
& 19.84 & 19.17 \\
& 21.52 & 10.09 \\
& 49.44 & 18.50 \\
& 27.91 & 18.16 \\
& 30.61 & 18.15 \\
& 16.14 & 18.83 \\
& 27.58 & 21.19 \\
& 15.47 & 17.16 \\
& 24.22 & 12.11 \\
& 70.97 & 16.83 \\
& 20.18 & 14.80 \\
& 17.49 & 15.47 \\
& 6.73 & 8.41 \\
& 25.56 & 11.44 \\
& 25.90 & 7.71 \\ \hline
\multirow{21}{*}{\textbf{Z3}} & 18.50 & 13.79 & \multirow{21}{*}{21} & \multirow{21}{*}{29.26} & \multirow{21}{*}{10.83} \\
& 6.73 & 8.07 \\
& 28.92 & 15.81 \\
& 10.79 & 10.32 \\
& 45.76 & 19.00 \\
& 14.14 & 5.96 \\
& 78.13 & 20.84 \\
& 38.90 & 11.11 \\
& 47.31 & 11.43 \\
& 21.86 & 7.74 \\
& 34.53 & 9.76 \\
& 14.47 & 8.77 \\
& 84.42 & 9.42 \\
& 7.06 & 8.43 \\
& 34.64 & 16.15 \\
& 14.80 & 6.05 \\
& 43.19 & 11.19 \\
& 16.55 & 7.96 \\
& 15.81 & 8.75 \\
& 14.13 & 5.72 \\
& 23.83 & 11.16 \\ \hline
\multirow{3}{*}{\textbf{Z4}} & 23.21 & 15.47 & \multirow{3}{*}{3} & \multirow{3}{*}{73.72} & \multirow{3}{*}{47.15} \\
& 55.25 & 15.48 \\
& 142.70 & 110.51 \\ \hline
\multirow{6}{*}{\textbf{Z5}} & 19.22 & 18.74 & \multirow{6}{*}{6} & \multirow{6}{*}{16.64} & \multirow{6}{*}{14.37} \\
& 15.76 & 7.39 \\
& 12.98 & 16.34 \\
& 22.58 & 17.30 \\
& 9.61 & 11.53 \\
& 19.7 & 14.90 \\ \hline
\multirow{7}{*}{\textbf{Z6}} & 12.91 & 12.02 & \multirow{7}{*}{7} & \multirow{7}{*}{28.41} & \multirow{7}{*}{12.21} \\
& 27.92 & 15.47 \\
& 27.87 & 15.86 \\
& 18.26 & 9.40 \\
& 32.67 & 14.46 \\
& 28.83 & 9.61 \\
& 50.45 & 8.65 \\ \hline
\multirow{6}{*}{\textbf{Z7}} & 105.75 & 72.50 & \multirow{6}{*}{6} & \multirow{6}{*}{4.75} & \multirow{6}{*}{23} \\
& 44.39 & 13.79 \\
& 53.49 & 24.57 \\
& 35.00 & 8.77 \\
& 56.22 & 8.64 \\
& 33.67 & 9.62 \\ \hline
\multirow{35}{*}{\textbf{Z8}} & 33.20 & 52.53 & \multirow{35}{*}{35} & \multirow{35}{*}{133.83} & \multirow{35}{*}{57.52} \\
& 50.78 & 20.52 \\
& 87.51 & 27.58 \\
& 44.06 & 25.90 \\
& 104.37 & 33.64 \\
& 97.20 & 48.77 \\
& 101.23 & 44.40 \\
& 151.05 & 47.90 \\
& 138.06 & 73.99 \\
& 704.85 & 133.42 \\
& 121.97 & 110.51 \\
& 312.00 & 161.73 \\
& 72.11 & 39.76 \\
& 102.43 & 67.39 \\
& 35.05 & 35.05 \\
& 30.32 & 30.32 \\
& 164.42 & 148.92 \\
& 49.97 & 26.28 \\
& 39.76 & 39.76 \\
& 55.16 & 31.68 \\
& 86.88 & 24.06 \\
& 73.45 & 67.42 \\
& 287.74 & 68.06 \\
& 199.46 & 72.11 \\
& 370.62 & 82.70 \\
& 61.32 & 53.91 \\
& 506.35 & 73.07 \\
& 167.5 & 190.52 \\
& 51.03 & 36.48 \\
& 166.54 & 54.87 \\
& 41.39 & 24.07 \\
& 70.63 & 10.53 \\
& 34.64 & 19.84 \\
& 44.73 & 19.17 \\
& 26.43 & 16.29 \\ \hline
\multirow{27}{*}{\textbf{Z9}} & 38.34 & 24.55 & \multirow{27}{*}{27} & \multirow{27}{*}{125.19} & \multirow{27}{*}{54.61} \\
& 286.55 & 44.73 \\
& 156.10 & 32.63 \\
& 188.68 & 48.53 \\
& 42.28 & 24.36 \\
& 154.08 & 47.42 \\
& 25.46 & 25.46 \\
& 58.62 & 40.21 \\
& 213.81 & 50.45 \\
& 111.95 & 57.18 \\
& 36.52 & 36.52 \\
& 171.53 & 77.84 \\
& 192.72 & 65.36 \\
& 284.37 & 65.00 \\
& 86.25 & 94.34 \\
& 35.00 & 35.00 \\
& 311.03 & 196.19 \\
& 96.36 & 45.17 \\
& 76.06 & 4.32 \\
& 38.61 & 38.61 \\
& 76.00 & 28.00 \\
& 28.00 & 28.00 \\
& 50.00 & 50.00 \\
& 84.72 & 53.92 \\
& 69.32 & 74.04 \\
& 282.06 & 76.05 \\
& 185.79 & 60.65 \\ \hline
\caption{\emph{Dimensioni dei Pit per configurazioni Z}}
\label{tab:pitdatiz}
\end{longtable}`