Since the results submitted date is simultaneously listed with the quality control return date, the submission apparently has no major pending changes. I am surprised this hasn't been PR'ed yet.
I assume you misread the page. The submission was March 22 and the return was April 19. They are always listed on the same line.
But certainly it is nothing major, has nothing to do with the quality of the data itself nor the trial. This is no more than a paperwork review. As long as they submit the required information it will be accepted.
It would be like the IRS saying you forgot to sign the form.