I have recently observed ( not naming the location ) an instance where a platform is bi-directionally signaled displaying something unexpected. The signal at the down end of the platform was off and the "DN OFF" indicator on the platform was lit. There was a train due imminently. A moment later, the signal at the up end of the platform cleared to off. So the signals at both ends of the platform were off simultaneously although only a down train was due. Did I observe a wrong side failure or an error?