Yes she could have done better and acted more responsibly during handover, but I feel u have no choice but to continue support her questions even tho FOC, because:

(1) Your legacy at ex company is in question. Anything go wrong, your ex colleague can say “this fler didn’t clarify etc”. Of cos it can also happen even if u help, that is part of corporate life, but at least try to minimize the blaming you will get.

(2) ur current employer has biz relationship with your ex employer, so this legacy thing could damage your future employers’ view of you too.

Anyway it’s quite common to help ex colleagues with questions up to 3-6 months. As long as not doing any work for them. It’s normal practice lah. I once had an email on my work more than 12 months after leaving.