When the waveform of INS-4040 was measured, the rise time was 1.9 ns. Is there a reason why it became slower?

When the waveform of INS-4040 was measured, the rise time was 1.9 ns. Is there a reason why it became slower?

The cause is considered to be the low bandwidth of the ATT and oscilloscope.
* 00-00017A: Since it is DC to 2 GHz, it can be checked at 1 ns or less.