Can wisc IV be wrong?

My child recently had a psychoeducational assessment and the result was average intelligence and severe ADHD. I immediately joined many ADHD support groups and quickly realized something felt off. My child has no emotional outbursts - in fact they have great control over their emotions for their age (8). They have no issues with executive functions - in fact they are very orderly and prone to planning in advance. They're social and easily make friends. They're never late and keep better track of time in the morning than my teen. My child reads above grade level, does math above grade level, teachers tell me they're mature for their age. Their speech therapist states their vocabulary is above average (something we also noticed) but the wisc iv stated their vocabulary is below average. However they are impulsive, extremely distractible when bored, fidgets, etc. In trying to figure out if they were misdiagnosed I learned giftedness could look like ADHD. However, wouldn't that turn up on the assessment? Is it possible the test was wrong, or my child didn't fully understand the assessor's accent or something so didn't understand the question? I want to help them but I can't if I don't know what's going on. Should I do a second assessment? I don't understand how someone could be gifted and have an average IQ result, but I also don't understand how someone could be ADHD without the major markers of ADHD.