Implications of a compressible LUKS1 header?

I have two external backup drives encrypted with LUKS and I have backed up their LUKS headers. Both drives are encrypted with the same ciphers, hash functions, and have the same passphrases. I noticed that the headers are the same size, but when I gzip them, one is uncompressible and stays at about 2 MiB in size, while the other compresses down to about a quarter of the size: 254 KiB. I first noticed that something was odd because I had used gpg to encrypt the headers and found the same result with the .gpg files. All the LUKS headers for my other disks are essentially incompressible.

My question is whether there's a problem with the LUKS encryption of my drive with the compressible header. Perhaps the encryption key is weak? Should I re-encrypt the drive with the compressible header?

Does anyone have an idea of what's up with the compressible LUKS header?