If the bad block appears in the area of the drive where the encrypted file data is saved, then the specific block will be unreadable as well. This is because encryption still works block-wise, allowing to read a random sector of a file or device.
Every block is encrypted using it's own encryption key (usually derived from the block address and the used master encryption key).
If one bad sector is unreadable, the corresponding block will not be (fully) be decryptable, too.
But there are more sensitive areas: Bitlocker and VeraCrypt maintain a section that contains the encrypted master encryption key. For data safety purposes this section is written at least two times, usually at the beginning and at the end of the encrypted partition/image. But if there would be a bad sector destroying both of them then all encrypted data would be undecryptable.