  In this note we consider $W$-shaped map $W_0=W_{s_1,s_2}$ with $\frac
{1}{s_1}+\frac {1}{s_2}=1$ and show that eigenvalue 1 is not stable. We do this
in a constructive way. For each perturbing map $W_a$ we show the existence of
the "second" eigenvalue $\lambda_a$, such that $\lambda_a\to 1$, as $a\to 0$,
which proves instability of isolated spectrum of $W_0$. At the same time, the
existence of second eigenvalues close to 1 causes the maps $W_a$ behave in a
metastable way. They have two almost invariant sets and the system spends long
periods of consecutive iterations in each of them with infrequent jumps from
one to the other.
