Gershon Dubin asked:
This limud from "Panai yelechu vahanichosi lach", Rav Yochanan says on amud aleph in the name of R' Yosi, and on amud beis in the name of R' Shimon bar Yochai?
The Kollel replies:
The Sifsei Chachamim points this out, and says that Rebbi Yochanan heard this teaching from these two rebbis of his, and thus said it over in each one's name. The Gemara quotes his statements in the name of each respective rebbi in the context of other statements that he says in their name.
If we find a deeper answer, we'll let you know.