Miscatagorization Disorder

Miscatagorization Disorder, commonly known as miscat, is a mental disorder unique to elves that affects memory recall and pairing on information.
Elves are a very long-lived race, and if anything tend to be able to recall more of their lives in better detail than the average human. The reason for this increased capacity, as far as it is understood, is that elves have a somewhat different process for categorizing memories and information mentally. In the vast majority of cases, this system is highly efficient, allowing elves to recall several hundreds of memory with relative clarity. However, on rare occasion this categorization process will malfunction, causing memories and knowledge to be paired up incorrectly.
The severity ranges, from slight enough that it appears as little more than a lapse of memory to severe enough to leave the patient and often those who know them highly confused.

Symptoms

The miscatagorization of memories ranges in exact form, but it tends to manifest and mis-pairing information: remembering most of an event correctly but replacing a crucial detail with something or someone else. This can range from swapping friends birthdays, to an adventurer assigning a learned weakness to the wrong monster, to in rare cases something as severe as misremembering which of their close friends they were married to.

Treatment

Treatment is still of mixed effectiveness, but it usually comes in the form of recategorization therapy: meticulously going through memories and learned information to set them right again. This doesn't always replace the faulty memories, but has proven effective in some patients, and with others at least helps them remember that their version of a memory isn't what actually occurred.
If the problem is caught early, recategorization therapy tends to be more effective, by keeping the memories properly categorized before the faulty memories have time to settle.

Type

Mental