Any ideas what could be causing weird max ramp behaviour on DM11?

Battery is a fully charged P45B, light is only a couple weeks old. This happens when ramping to max from anywhere. 2C from off works fine, but trying to ramp from there causes this behaviour immediately. There also seems to be no difference in brightness between max ramp and turbo which doesn’t seem right. It’s not in simple mode.

Thanks

by oscailte