I couldn’t find the original thread with this issue, but I believe I just had it happen to me as well. Forging Topaz Bombs: used 1 invigoration paste 2, 2 longevity gum then 2 effect gum, then basically used Fate Paste 2 and Pure Boon Compound 3 in proper order until done. Boons in order (from bottom up) were Energy Saver, Devastating Damage, and Bigger Boom.
Energy Saver was not yet filled in the final rounds of forging. I rolled a good enough roll to get it up I think to 4 levels, left the forge mid-fill and came back in to the first boon slot reverted back to its non-filled state. Stability and vigour had also been used. The final roll had brought my vigour down to a count too low to continue. I set the gear just in case it was a UI issue, but have confirmed the Energy Saver boon was not applied.