Negative lag

I have a hard deadline for which I am creating negative lag relationship with predecessor tasks to create the plan (ie, the meeting date is a hard deadline on 5/7, the draft agenda is due 5 weeks before the meeting, so a negative lag dependency of 5 weeks).  Negative lag appears to work in Clarizen up to a point, for example -2 days works, -5 days works, but beyond that it allows me to put in negative lag time frames but does not recalculate the "draft agenda" task.   Is this a known issue with Clarizen?

Thank you.

I-610028