Sometimes server lag will rubberband an SC stone out of the enhancement window as well without you noticing. Always put the SC stones in before the elrue/lix/xir and give it a moment before hitting the enhance button to help ensure all SC stones are properly in place.
Recent update allows stacks to be placed in slots so lagging out of the slots should not be possible.
Just sayin'... they already have the text log in-game for the player. You'd think they would store information like that, at least temporarily, for these very kinds of glitches/instances.
Client side log isn't trustful and doesn't tell which items were used.
It seems strange that Fiesta doesn't have a running log on the back end that shows what items were used in enhancement. That seems like a fairly significant gap.
They probably do have a log for it, but either its a hassle to look through like to find the specific person/time or they do and they don't find anything wrong in the logs, like it might show as there being no stones.
I would say that they don't have it as otherwise they wouldn't call you liar:
Mr. Nico, called me a liar and said that I had not used these stones on this date abd that I would not return my item.
Seen videos of it this happening as well.
If there is video proof that its possible then it should be fixed. Either by just increasing the break rate reduction (100%->150%) or fix the code (feels like some sort of conditional is wrong which doesn't include the edge case (so there would be 0.01% chance of breakage or something)).