In ZWEI in Experimental System 204.26, Experimental ZMail 42.4, Experimental LMFS 23.18, Experimental Tape 8.0, Experimental Symbolics 10.1, Experimental Canon 12.3, microcode 865, on Spaniel: It seems that, after the first time I do M-. INTERVAL-IO, Zwei must resectionize the buffer every time to find it.