It's not every time for me, but it's close and it's been like that for a long, long time. Sometimes I can't even map it. Sometimes it works OK when in a project but then the project crashes every time I try and open it.
From my (many) searches online I think we're far from the only ones and to me this seems like such a fundamental thing to be so unreliable. Disappointed it hasn't been redone as a native device.
Convolution reverb has also tended to be a bit sketchy for me but at least part of that is in the native 11 hybrid reverb now.
Have you tried Robert Henke's free M4L LFO 2.0? I think I'm going to start defaulting to that from now on myself but if anyone knows any other really stable ones I'd love to hear about them!