Complex sentence: These anomalies are believed to have been caused by the unanticipated 15 month delay in module inflation: this may have resulted in the stiffening of flexible membranes of the module during storage.
Split into simpler sentences: These anomalies are believed to have been due to the unanticipated 15 month delay in module inflation. The long delay may have resulted in certain stiffening of certain flexible membranes of the module during storage.