Hello! My name is Rocio, i've been having trouble finding the answer to this issue, will post an image so I can show you. Help is appreciated! Thank you!
In the top right corner should be a drop down menu next to the folder name.
Select "Edit Current View", which will jump you over to the SharePoint site, where you can turn on and off various columns. See if the modified/modified by columns were turned off. See if that helps.
