Is Cuendillar weakening?

Question

In the books, the seals of the Dark One's prison, which are made of cuendillar, are more or less decaying away as a plot point. Cuendillar is indestructible by lore and only gets stronger if you try to use the power to destroy it.

As another plot point, after the usage of the Bowl of Winds, it is shown that the power is reacting to a sudden change and altering the behavior of their weaves, however slightly, and seems to be a general complication of any great deal of channeling in general.

Is there any other reference to the nature of existing cuendillar changing, or are only the seals affected as far as we have been told so far?

Answer 1

There haven't been any sign of other cuendillar weakening. The weakening seems to be related to the fact that the seals are touching the Dark One. Nynaeve feels evil emanating from one of the seals on the way to Salidar, and the feeling is gone when they show the broken seal to the Aes Sedai after they arrive.

The Bowl of Winds issue is separate. WoTFAQ

Answer 2

Other cuendillar items haven't been seen weakening as a whole, although maybe some individual pieces could 'rot', as the Dark One's touch corrupts the whole land.

We have a very definite example of cuendillar not being weak in a plot revolving around Tar Valon and its docks, which is spoiler material (books 12, 13).