4.16.2
In a dynamic parameter, you can not interpolate a value in DP0 / red channel unless you have “Spawn Time Only” turned ON in the alpha channel.
This means you can’t interpolate values in both the red and alpha channel at the same time. There is no problem interpolating red and green at the same time - it’s just the alpha channel that seems to cause problems.
I attached a test particle and material - note that the particle should turn from green to yellow, but it will not work unless you turn on “Spawn Time Only” in the dynamic parameter alpha channel.
Probably related to / same as this bug (in which case, please +1 community interest in fixing because it took quite a while to debug). I’ve worked around it for my case.