I am currently validating a PCB that uses the THVD1450DRBR RS485 buffer chip and I am facing two issues. The first is that the signal, when toggled, will pulse very high or very low (>6V when change in magnitude should be 3.3V or less) for about 10 microseconds before reaching its intended output value. In the image below, see the green input toggling from low to high, upon which the yellow output pulses high before going to its target value of about 3.2V. The same happens on the falling edge of the input from 3.3V to 0V.
The second issue is that the signal is not maintaining its strength through the whole system. This RS485 signal travels out of its origin PCB and to another, but by the time it reaches the second PCB, the signal falls in magnitude. See below. The output signal probed right at the output of the buffer on the origin PCB (yellow) is higher in magnitude than the same signal (green) probed at the next PCB over. The signal is losing much of its strength over this period and continues to lose it across a third and final PCB (not pictured). Why is the signal not driving strong enough? Is there anything I can do to fix it?