Upload files bottom disappeared in reviewer account

Dear all,
@asmecher @israel.cefrin

One of the reviewers reported that Upload files bottom in Download & Review stage disappeared. I checked it and have

image

I am using Ojs 3.1.0.0

Sorry, after confirming to the reviewer whom reported the issue, it is said that the bottom existed but failed to upload the file with not support notification. I could not get enough information about the notification. So, we need to ask other reviewers about this issue.
My question, is the bottom disappeared as in attached picture when reviewer confirms the decision?