H4 EAD & I94 Expiry

My wife’s H4 EAD expires on Jan 22, 2020. Her I-539 (extension) application is pending approval with the USCIS (bio-metrics completed). Her I-765 application is also pending approval with the USCIS. Her I-94 is valid up to Feb 1, 2020. Her employer is stating that per her I-9 and I-94 she is legally allowed to work until Feb 1, 2020.
Is this true? I believe that she is not legally allowed to work beyond the expiry for her EAD and we’re willing to wait for her EAD. What is (legally) the correct way to handle this situation?