Wally and Jay have spent extended periods in the speed force, and neither one came out with pre-packaged memory loss.
That Barry remembers nothing of when he was acting crazy potentially nixes Cisco’s belief that Barry was attempting to send a secret message to the team.
Barry returned from the Speed Force in a confused state and started going full-on John Nash as he littered any and all walls with symbols that Cisco eventually translated to “This House Is Bitchin’.” The line meant absolutely nothing to Barry when he snapped back to reality, which itself is understandable, but isn’t it weird he didn’t even remember it (or anything else from his fugue state)?