First time it's used it works perfectly. Second time it fails to boost evasion and then visually (no actual boost) raises the attack stat 76 stages.
I recall this being reported before in some way. I forgot what the solution whatever was. EDIT: Found it. http://pokemon-online.eu/threads/41-generation-1-ditto.28945/ Looks like that time it was a transformation flag missing... I guess ill look into this when i get a chance
Submitted fix for the boost fail, but I wasn't able to fix the tooltip displaying that the attack stat rose.
Merged turbedi's fix and then fixed the tooltip... which was a lot more than just a tooltip issue (it prevented you from boosting your attack after you have boosted your evasion)