Final answer:
The sentence that uses the underlined word incorrectly is: The core issue that causes troubles with my ability to spell is my diagnosed Dyslexia.
Step-by-step explanation:
The sentence that uses the underlined word incorrectly is: The core issue that causes troubles with my ability to spell is my diagnosed Dyslexia. In this sentence, the word 'diagnosed' is used incorrectly. The word 'diagnosed' should be used with a specific medical condition, whereas in this sentence, it is used with 'Dyslexia' which is already a diagnosed condition and does not require the word 'diagnosed' before it.
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