Why doesn't updating a particle settings object `frame_start` field work? (in Blender 2.8) I am creating a ParticleSettings object from python (Blender 2.8). All of the properties are set correctly but for frame_start, which does not change. Any ideas of why?

ps = modifier.particle_system.settings
ps.count = num_particles
ps.frame_start = explosion_frame
ps.frame_end = explosion_frame + 2
ps.lifetime = FPS * 3
ps.emit_from = 'VOLUME'
ps.normal_factor = 3
ps.tangent_phase = 0.5
ps.tangent_factor = 3
print(ps.count, ps.frame_start, ps.frame_end, ps.lifetime, ps.emit_from, ps.normal_factor, ps.tangent_phase, ps.tangent_factor)
The problem was that I was setting frame_start first, to a value greater than the current (at the time) frame_end. frame_start needs to be less or equal than frame_end. The following version does work.

ps = modifier.particle_system.settings
ps.frame_end = explosion_frame + 2
ps.frame_start = explosion_frame