If I have a fleet with a ship containing a warp bubble (of any variety) the first turn back after loading a saved game the fleet will not use the warp bubble in its movement.

Ship A: 4 mp and +3 warp bubble
Ship B: 5 mp
Ship C: 5 mp

This fleet would show 5/8 as its movement speed. It has not moved yet for the turn, and it can only move 5 spaces (so Ship A is getting some bonus mp)

Even if I saved the game at the end of a turn, all movement completed, and then loaded that saved game, hit the End Turn button, and went to the next turn, that first turn of movement would result in the above example.

This is using the Terran warp bubbles at least in this game.