LJ25 FLC ADVISED BY PLT AN ATC THAT A B737; THEN AN AIRBUS HAD INITIATED A TCASII MANEUVER DUE TO A MODE C READOUT. AFTER CHANGING XPONDERS TWICE; NO ADDITIONAL BAD HITS WERE OBSERVED.

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DURING CRUISE FLT AS AN ALT IN THE MFD 20'S (FL200-FL290). I WAS IN LEVEL FLT WHEN A B737 CRUISING 2000 FT ABOVE ME STATED HE WAS EXECUTING AN EVASIVE PULL-UP FOR A TCASII WARNING HE HAD RECEIVED ABOUT MY ACFT. THEN; SECONDS LATER; HE TOLD CTR THAT IF WE WERE 2000 FT APART AGAIN. I DID NOT CHANGE ALT. THEN WITH THE NEXT CTLR; WE WERE GIVEN A CLB TO FL330. WHEN I LEVELED AT FL330; THE ATC CTLR SAID HE HAD ME AT FL337 AND CLBING. MY COPLT SAID WE ARE LEVEL AT FL330. THE CTLR QUESTIONED OUR ALT AGAIN; AND MY COPLT SAID WE ARE DSNDING. WHAT HE MEANT WAS WE WERE 150 FT HIGH AND CORRECTING ARE ALT TO LEVEL AT FL330. SHORTLY AFTER THIS HAPPENED; I SWITCHED TO OUR SECONDARY XPONDER AND NO OTHER PROBS OCCURRED WITH OUR ALT RPTING; BECAUSE THERE WAS AN AIRBUS CRUISING AT FL350 WITHIN 3 NM OF OUR POS. ZKC IS INVESTIGATING THIS INCIDENT. LATER THAT DAY; ON A DIFFERENT LEG ON ZFW; I SWITCHED BACK TO OUR PRIMARY XPONDER. THEY SAID IT WAS WORKING GOOD. WHEN THIS LOSS OF RADAR SEPARATION OCCURRED WITH ZKC; MY ACFT WAS NOT MORE THAN 150 FT OFF ALT; AND THAT WAS ONLY FOR THE LEVEL OFF. EITHER THE CTR RADAR HAD A PROB OR MY PRIMARY XPONDER WAS RPTING MODE C INCORRECTLY. EITHER WAY; ACTUAL PHYSICAL LOSS OF SEPARATION BTWN MY ACFT (LEAR JET 25) AND THE AIRBUS CRUISING AT FL350 ABOVE US WAS NEVER LOST. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR WAS UNSURE WHO'S EQUIP PROB IT WAS. CTLR SUPVR ADVISED THAT THEY WERE 'LOOKING INTO THE EVENT.' RPTR HAS NOT BEEN ADVISED OF ANY FURTHER RESOLUTION FROM ATC.