John, I don't want to worry you but when I bought a new cat for my old 4/4, there was a warning not to use exhaust sealing paste upstream of the cat as it could damage the matrix if it gets inside.

Also invalidates the warranty.

See warning label below.

Hopefully none of it got squeezed inside.

[Linked Image]

Bob

2009 Black Roadster
1999 4/4 2 litre Zetec