Suggestion: Block spending Influence to complete Pacific Conversion until greater than 50% progress.

Currently, a faction can take any system overlapped by Influence bubble if they have enough Influence and are in the Diplomatic state of Cold War or Peace. What this means in practice is that the enemy AI will spend all of its Influence buying out systems in their Influence bubbles the turn that a Truce ends. It becomes a race between the player clicking through the Diplomacy menu to Declare War or the enemy AI spending Influence to complete the conversion early.

Delaying the Buyout decision until 50% progress would give more time for the "Stop Influence Conversion" Diplomacy context action to take effect. It also takes 13 turns for a system handed over in a Peace Deal to reach 100% Control and even start generating an Influence bubble from 0. Also, the game doesn't even warn you that Pacific Conversion is in progress until a certain threshold is reached.

TLDR; 

I want to stop being forced to Truce Break 1 turn early to prevent Instant Conversions.

I feel like because it's so aggressive, they've had to code the AI to respond to it incredibly aggressively. This means an AI with no fleets will declare war to reset the timer, then immediately offer a Truce. War every 10 turns for the rest of the game(or until you forcible stabilize the borders somehow by taking all their systems in your influence zone).

The only counterplay to Influence conversion is War. The Diplomatic context decision is currently useless, increased Pressure from diplomatic decision doesn't matter during War.

I certinaly get where an aspect fo this comes from in so much as the whole "force a war" aspect is a little instant once things reach a certain point. But at the same time a major purpose of it is to force fights between races that aren't allies. The ideal would be that an attempted conversion would give the player the opportunity to declare war to prevent it from happening once clicked, (with an influance refund for the converting player), and the cost should likly be higher to make it harder to convert the moment you get coverage, (posibbly it should be a cost that decreases each turn). That gives everyone some leeway and reactionary options.

There are only 2 factions immune to influence conversion: Unfallen(thanks to their Vines) and Vodyani(which has Peace and Prayer Act that makes their Arks and the system's they're anchored to immune to it). For everyone else... its basically full on War lest you have your systems stolen right out from under you. Could a 50% threshold be the ultimate fix to this? Possibly but if you're conquering systems, sometimes occupation may not be the best option when achieving victory in ground battle.