Why aren't you running the latest version of Opus? If you think Opus may be doing something wrong, get the latest version so we're not potentially wasting time talking about something that has already been fixed. (OTOH, if you don't think Opus is doing anything wrong then I don't see how this forum can help. 
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What happens if you look at the files in Explorer? Depending on how the files are being updated, file-size changes do not always trigger change events that file managers can monitor. Sometimes the size-change notification only happens when the file is closed at the end of the update.
If Explorer does detect the changes while Opus does not, see the Changes to folders are not being detected FAQ for steps to diagnose what's going on.