Difficulty doing something or difficulty to do something

I know you can't say have difficulty to do something:

• Oxford Advanced Learner's Dictionary
• Longman Dictionary of Contemporary English

But to my surprise, I saw it in an English textbook that I'm teaching:

I believe it should be:

insomnia: difficulty getting to sleep and sleeping well

I just want to make sure the writer has made a mistake.

No, you cannot say 'have difficulty to do something'. 'have difficulty (in) doing something' will do instead. I've just checked the oxford dictionary again. You are right.