Why does error propagation in CBC mode encryption affect two blocks? From Wikipedia:

Error propagation
It was common to discuss the &quot;error propagation&quot; properties as a selection criterion for a mode of operation. It might be observed, for example, that a one-block error in the transmitted ciphertext would result in a one-block error in the reconstructed plaintext for ECB mode encryption, while in CBC mode such an error would affect two blocks.

I read this similar post before. And I can understand that in CBC decryption, only two blocks are affected due to error propagation (error in 1 block).
But, for the same case in CBC encryption, why are still only two blocks affected? It looks like all the following blocks will be affected.
Encryption process in CBC mode is performed as
\begin{align}
C_1 &amp;= Enc_k(P_1 \oplus IV)\\
C_i &amp;= Enc_k(P_i \oplus C_{i-1}),\;\; 1 &lt; i \leq nb,
\end{align}
where $nb$ is the number of blocks.

CBC is designed for chaining, therefore while encryption, if there is one block error at position $i$, it will affect the rest of ciphertext. This also can be seen from below if write the equation of encryption of $j$-th block.

$$C_j = Enc_k(P_j \oplus Enc_k(P_{j-1} \oplus \cdots Enc_k(P_1 \oplus IV)\cdots)).$$ If $i &lt; j$  then the $j$-th plaintext block will be affected.

However, while decryption of the ciphertext, that is encryption of the plaintext that contains the errored block, you will get only one block with error, the errored plaintext block. Or simply, you will get what you encrypted if there is no error/corruption on the ciphertext blocks.

Note: if there is an error on one of the ciphertext blocks, it can affect one or two plaintext blocks depending on the index of the ciphertext block. One block if the last ciphertext block is corrupted, two blocks otherwise, see bit flipping attack to visiualize. The question is on the error on the plaintext.