As the topic title says:
Convolution reverb can loose its setting when relaunching Live and restoring the set after a crash. It's random, it doesn't necessarily happens to all the instances of the set.
Problem still here in 9.0.4 (max 6.1.0 , osx 6..
Please update to MAX 6.1.3 and reproduce the crash.
Send in the crashpack to crashes@ableton.com and when you see the reverb loosing its settings, please send a status report to beta@ableton.com
I was also having this issue so I logged it with support and the loss of settings was reproducible. As such, it's been officially filed as a bug so hopefully we'll see a fix for it some time soon