I have the exact same thing happening to me with a GEMB/Sam's Club acct. that was IIB in Aug. 2006. Every month they report account status and for some reason FICO interprets it as a "missed payment". Although there are no "lates" being reported I must be taking a hit to my FICO score. It's making me crazy, I have disputed twice with no changes.
FICO scores on November 17, 2014 (prior to applying for and being approved my mortgage)
EX=738
EQ=735
TU=754
FICO scores on March 4, 2015 after being approved for mortgage and buying the home, the mortgage isn't yet reporting.
EX- 689 EQ- 739 TU- 739