It's actually incredibly common. If a company has ever had an issue around reporting, they need to include that. See here how many companies use the same exact language:
Isn't it more the second part of the statement that is shocking, that is "may identify additional material weaknesses in the future" rather than "we have identified a material weakness".
If so, that cuts the results down from 684 to 205, of which many are from the same company, just at different times.
https://www.sec.gov/edgar/search/#/q=%2522we%2520have%2520id...