You're looking at the "Cumulative-to-Date" data of the six-period summary report for your program and notice an inconsistent pattern in the Schedule Variance.
September 2018: 249.5
October 2018: -147.8
November 2018: -100.5
December 2018: 98.4
January 2019: -273.9
February 2019: -166.8
What does this indicate?
The schedule is too aggressive.
For some reason, the control accounts are not maintaining a consistent delivery schedule for their tasks.
Nothing, this pattern is normal for a large program.
The Control Account Managers (CAMs) are unable to get their workers to work efficiently.