This is not a new issue. This happened in the Big 10 many years ago. In 1987, Chris Carter signed with Norby Walters and was ruled ineligible. He talks a little about this in this ESPN video from this morning's Mike and Mike program.
Ironically, Carter's son Duron played wideout at OSU and started some games. He was forced to transfer to a community college due to academic issues this year.