With HTML 5 Packages you cannot use the windows clipboard to paste things into the text box. This issue does not occur with other builds of the project. This issue does not appear to be a regression
Versions Tested: Issue occurs in all versions tested
4.16.3 - CL: 3561208
4.17.1 - CL: 3586342
4.18 - CL: 3641171
Head over to the existingAnswerHub thread and let us know what's up.