I have been using S3 configuration like that for almost 1 year ago.
and my issue just came up recently.
if I upload via web interface, for example .pdf or .doc file, then the file changes to a folder like this:
Anything that changed recently? New app installed?
This version is not supported any more. NC 28 is the lowest still supported version. And regarding the NC 26 branch, it is recommended to install the minor updates (26.0.2, 26.0.3, …) rather quickly since it fixes bugs (also security). And they do not add features within the minor updates or change dependencies.