Sample request: https://www.wikidata.org/w/api.php?action=wbgetentities&format=json&ids=L44929-F5
Result:
{"error":{"code":"internal_api_error_BadMethodCallException","info":"[XPfvJApAIDQAAFhIrG8AAACG] Caught exception of type BadMethodCallException","errorclass":"BadMethodCallException"},"servedby":"mw1340"}
There must be an error but used to be none. Getting whole lexemes works.