LT3462 How to use

After simulating the LT3462 with the recommended circuit, there were no problems, so I mounted it on the board.
When the input is set to 15V DC and the output is set to 18V,
The output changes from about -19V to about -18.5V,
A triangular waveform of several MHz is different in the output by about 50 mV.
I am troubled because it is different from the set voltage and abnormal oscillation occurs.
The pattern of the board is made similar to the recommended pattern.
Is there a recommended constant for normal operation?
please tell me