I can confirm that the style when opened on a Mac or Windows machine that the template for a Journal article has lost the spaces and punctuation around all the fields expect Volume.
I was able to add the spaces and punctuation then save the style with a new name. The changes were retained when previewing the style and reopening it.
You might want to check the location of where output styles are getting saved on your machine.
Windows:
Edit then Preferences then Folder Locations.
Mac:
EndNote menu then Preferences then Folder Locations.
If the path for the Styles folder includes a location that is set sync with a cloud service like DropBox or iCloud that could be related to the issue.
Please find the edited version of your style attached.
CSIE 2020.zip (2.76 KB)