I have noticed 2 bugs that prevent the pre-chat popup from allowing users to get to the LiveChat window. Trying over and over sometimes works, so it looks like race conditions to me.
Select "other" for both the dropdowns and fill them out. Submit button stays greyed out even when form is completed. (Might need autofill active for this.)
Chrome AND Safari
Finish the form and submit, the modal closes and nothing happens. (Chat icon is gone.)