Major Most, but not all, rules for URI path parts define a leading slash and no trailing slash.
Unfortunately some of these rules are used in places where no leading slash is allowed (property names in $filter, $orderby), see ODATA-28 and ODATA-29.
Also a few other rules or rule parts define neither leading nor trailing slashes, leading to missing path separators, or explicitly introduce a trailing slash, leading to two consecutive slashes.
At the root of this issues lies the question: does the serviceRoot have a trailing slash?
The spec explicitly says "No", while most server implementations explicitly say "Yes", and redirect from the slash-less path to the path with trailing slash before responding with 200 OK.