Using currently 3.2.1.2. When someone with the required permissions clicks on Request Revisions at the Review stage, a window opens up with checkmark options for there being another round of review or not. Strangely, although this didn’t happen in earlier versions of OJS, if the choice is made to require another round of review (leading to the status of “The submission must be resubmitted …”), authors cannot upload a revision file, as shown in the attached screenshot. Only if “Request Revisions” is selected again (or at some point) and the choice is made to NOT have another round of review (leading to the status “Revisions have been requested”), does it become possible for the author to upload the revised review file.
Same bug as also reported in this thread: Revisions > Upload File, Access Denied for author in OJS 3.2.1-2