I aggree with you that it is probably a bug. If you do not keyframe the Lifetime everything is fine. This might be based on the same issue as in the bug report you found or something completely different, I don’t know… is it a baking thing or a particle system problem?
The strange thing to me is, that most people don’t seem to have this problem!
The particle system is being re-written., so it might get solved ‘automatically’, but I will see if I can re-create the issue with a simple .blend file and report it as a bug.
