A B737-300 FLT CREW FAILS TO MAKE A LOGBOOK ENTRY REGARDING A MALFUNCTION EXPERIENCED WITH THEIR PRESSURIZATION SYS ON A PREVIOUS LEG. THE NEXT PIC HAS A PROB WITH THE SYS AND CALLS THE FIRST CAPT ON HIS LAYOVER TO FIND OUT IF HE HAD A PROB WITH THE ACFT.

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WE NOTICED THE CABIN RATE INCREASING AT CRUISE AT APPROX 100 FPM WITH A LOWER THAN NORMAL DIFFERENTIAL PRESSURE. INITIALLY GOING TO PACKS ON HIGH CORRECTED THE 100 FPM INCREASE. WE USED STANDBY MODE IN CRUISE AS A PRECAUTION AND SWITCHED BACK TO AUTO AFTER THE CABIN STARTED TO DSND PROPERLY DURING DSCNT. THE NEXT LEG EVERYTHING WENT FINE IN AUTO WITH A MAX CRUISE ALT OF FL270. THE NEXT MORNING; THE CAPT WHO TOOK OUT ACFT NUMBER CALLED ME AT THE HOTEL TO SEE IF WE HAD ANY PRESSURIZATION PROBS WITH THE ACFT. THEY HAD EXPERIENCED AN AUTO MODE FAILURE WITHOUT IT SWITCHING TO 'STANDBY' AND HAD TO DSND TO GET THE CABIN PRESSURE UNDER CTL. ON THE INITIAL FLT TO TUL; THERE WAS WX AT DEST AND A LOT OF COORD WITH DISPATCH ABOUT ENRTE WX FOR THE SECOND LEG; SO THE ANOMALY WITH THE PRESSURIZATION ON THE FIRST LEG WAS NOT WRITTEN UP. ON THE TERMINATION POSTFLT; THE FO FOUND EVIDENCE OF A BIRD STRIKE; SO THAT WAS ENTERED INTO THE LOGBOOK AND MAINT WAS NOTIFIED. OBVIOUSLY LOOKING BACK; A WRITE-UP BY ME ON THE INITIAL LEG WOULD HAVE BROKEN THE CHAIN OF EVENTS THAT COMPLICATED THE NEXT CREW'S DAY. THE ROUTINE NATURE OF DEALING WITH THE INITIAL ANOMALY AND SUBSEQUENT COORD EFFECT WITH DISPATCH REF THE WX; SIMPLY PUSHED THAT OCCURRENCE DOWN MY LIST OF PRIORITIES.