Difficulty lying
From ActuallyAutistic Wiki
Many of us have difficulty lying.
Autistic people often have a strong sense of justice and/or truthfulness. This can make lying difficult, painful, or impossible, even if it is a harmless "white" lie (such as saying you liked something you didn't) or a beneficial lie (such as in a job interview).
The need to tell the truth can naturally create difficulties for autists that many allistic people may not experience. Despite these difficulties, however, autists may take pride in their truthfulness, as it is hard to argue for a less truthful world.