There is a problem with using DES as the block cipher in OFB mode, eg: the feedback that goes back into the next round will be encrypted with the same key $k$ resulting back into the plaintext IV used in the first round, and this goes on and on until OFB is done.
So the output of the block cipher is deterministic and repetitive.
So, as we know using a feistel cipher has the nice property that running it twice through the cipher (with reverse ordening of subkeys) results back in the plaintext, so is it ok to say that the problem with using DES in OFB mode is true for all Feistel ciphers? Or is the reason that DES has a problem with OFB something different?
Thanks again for the clear response!
[EDIT] My initial assumption was wrong, the problem that encryption something twice with DES is a result from using a "weak key" not from the feistel structure. Sorry.
So to be sure, with DES, only when you encrypt something twice with a weak key. You get the back the original plaintext? So when using DES in OFB mode with a weak key would result in information leakage.