हम आ सकती हैं should also be accepted (if हम refers to a group of women).
You can report it if you encounter the sentence again.
not sure why the hai has to be included as the sentence does not include to be.
In Hindi, we need to include the है in all present tense sentences in order to identify them as being in the present tense. (Exceptions are sentences with चाहिए where it is not included and negative sentences where it is optional)