When this signal is a value of 1, it indicates that the error detection logic has identified a mismatch between the expected and received value of CRC24 in a Control Word.
Every time a CRC24 error is detected, all open packets are marked as containing errors as specified by the Interlaken Protocol Definition, Revision 1.2, October 7, 2008. By definition, there is no mechanism provided by Interlaken to associate a CRC24 error with individual packets.
This signal is asserted for one clock period each time a CRC24 error is detected.