I’ve set delimiter to semicolon but templates are exported with comma as separator (v3.29.1).
Bug maybe?
Do you mean when exporting a view? Then yes, it uses the delimiter that you selected here. See screenshots:
Default is set to a comma, so you will get a CSV with commas as the delimiter.
If I change the delimiter to a semicolon and download the view again, I get a semicolon as the delimiter:
Make sure the software you are opening the CSV with is not changing the semicolons to commas.