ARTCC ASSOCIATE DEVELOPMENTAL CTLR; WITH INSTRUCTOR; AND RADAR CTLR DEVELOPMENTAL; WITH INSTRUCTOR; APPARENTLY NOT AWARE THAT LOSS OF SEPARATION IS TAKING PLACE AT THE RADAR CTL POS. DSNDING ARR ACR CONFLICTS WITH XING ENRTE ACR.

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ACFT #1; NBOUND LEVEL FL310. ACFT #2 AT FL350 ISSUED DSCNT TO FL280. 3 MINS LATER; CONFLICT ALERT ACTIVATED AND ACFT ENDED UP WITH THE ABOVE SEPARATION (3 1/2 NM HORIZ/900 FT VERT). (CONFLICT ALERT ACTIVATED 33 SECONDS BEFORE LOSS OF SEPARATION.) SUPPLEMENTAL INFO FROM ACN 406274: AFTER REVIEWING MY TRAINEE WITH HIS D-SIDE FUNCTIONS; I SAT BACK DOWN IN MY CHAIR. CONFLICT ALERT ACTIVATED AND THE RADAR CTLR WHO WAS ALSO BEING TRAINED TOOK ACTION. SUPPLEMENTAL INFO FROM ACN 406336: #1 ACFT WAS DSNDED TO FL280 FROM FL350 WITH NBOUND TFC AT FL310. I DETERMINED THE #1 ACFT WAS CLRLY AHEAD OF #2 ACFT. EITHER THE COMPUTER GENERATED DATA ON ACFT #2 WAS INCORRECT; OR THE ACFT DEVIATED TO VIEW YOSEMITE NATIONAL PARK. CONFLICT ALERT ACTIVATED 17 SECONDS PRIOR TO LOSS OF SEPARATION. SUPPLEMENTAL INFO FROM ACN 406705: I WAS TRAINING A CTLR CERTIFIED ON ONE OTHER RADAR POS. WE HAD JUST FINISHED SEQUENCING A LINE OF ACFT TO SFO. ACFT #1 WAS THE FIRST ACFT IN THE NEXT STRING. WE WERE DISCUSSING THE SIT THAT WAS JUST FINISHING UP; AND PLANNING FOR THE NEXT SEQUENCE. THE TRAINEE DSNDED ACFT #1; THINKING THERE WAS SUFFICIENT SEPARATION.