I've noticed that Careful Synthesis, a skill that is currently billed as offering 90% Efficiency and 100% Success Rate, is mysteriously and randomly failing on the very last step of synthesis when the progress gained from using the skill will clearly complete the effort. I've noticed this behavior while grinding out recipes for Alchemy.

I can understand if there are external variables that might cause Careful Synthesis to fail (weather, etc.), but I have yet to see a tutorial window or disclaimer in the tooltip for the skill that suggest the 100% Success Rate can be otherwise diminished.

Requesting explanation or verification for this behavior.