Serial read functions, break the Servo library.

Using official Arduino mega's communicating over serial I see an issue. When ever a "readbytes" "readbytesuntil" "read string" "read string until" is used the Servo library becomes unstable. Specifically the Servo pulse has the right pulse time(1.5ms) but the frequency increases from 20ms to 300ms. I have verified this with multiple boards and multiple arduino versions. 1.06 and 1.6.4. I wrote my own Read function using the base Serial.read and it does work. Not sure if "readbytes" uses a the same timer or what? Thank you for your time.
-Joe