PHPDocs invalid integer values

The generated phpdocs contains some wrong documentation in the function core_course_get_contents.

The documentation says in the response that the keys modules[0]->contents[0]->timecreated and modules[0]->contents[0]->userid is not optional and an integer. But when I call it (sometimes) returns a null value on these two keys which is an invalid value for an integer.

Example response:
[{..., "modules":[{..., "contents":[
{"type":"file", ..., "timecreated":null, "timemodified":1525700516, "userid":null, "author":null, "license":null}
]}]}]