Calling GraphQL endpoint throws exception on API limit checks

[nikemeal]

When calling the GraphQL endpoint (/admin/graphql.json) it'll throw an exception when trying to work out the number of API calls made/left in Client.php on the first line of this function:
protected function setCallLimitParams() { $limit_parts = explode('/', $this->last_response->getHeader(self::CALL_LIMIT_HEADER)[0]); $this->call_limit = $limit_parts[0]; $this->call_bucket = $limit_parts[1]; }
with the error

Undefined offset: 0
due to the way GraphQL returns data.
Commenting out the checks for API limits allows it to work, but then means call rate limiting is redundant