I use Windows 11 and Everything 1.4.1.1015 (also tested alpha 1.5a), all settings are default and unchanged except indexing folder size and I randomly noticed that some folder sizes reported by Everything are not matching what windows reports. So I did a bit of digging and it seems Everything is not registering updates for some files, like in this example:
Sometimes the size/modify date updates after I open the file but often I can force the update only by rebuilding the index. Again, I didn't modify any settings except enabling folder size indexing.
Windows uses some kind of log journal to store all changes to files/folders. The journal entry of a file doesn't get updated until the file is closed. I guess your file is still be written to (by steam I suppose)
Everything gets file updates from this log journal and will show the old size too. As soon as your file is no longer in use, the filesize in Everything will be updated.
Workaround is to use Folder Indexing instead of NTFS indexing. Now the same size as in Explorer will be shown in Evverything.
(not recommended though, as NTFS indexing has more advant