I just started a new game 3.95. I chose the Pragmatic Ideology Neutral to prevent war for next 50 turns. I'm on turn 31. The Drengin just declared war on me. Note I didn't choose this until about turn 10 but either way the game hasn't been running for 50 turns yet. I'm also at war with the Krynn but that was done prior to me choosing that ideology.
It appears you changed your support structure as I had created a support ticket on this issue, and was referred to forums, in the past all bugs/issues were reported via support ticket. Either way, I have a saved game reflecting this if you would like it to reproduce or to confirm the issue is present to fix.