You did answer your own question. If it were someone looong to continue to network with an industry colleague, that’s completely different. Plus, if she’s a gossip, others will know that and you should not be seen associating with her, especially as you did not do so at your previous company.
I once happened upon one of my current employees meeting with several former employees, two of whom had tried to stage a coup and organize their own collective bargaining committee for part-time workers. When I said that the jobs they had were spelled out at the time of hiring, and met our business model, and that I was not changing it to suit them, they walked out. It was awkward to see their loud and foul mouthed leader, but for the current employees, since she was joined by a duplicitous guy who lied to get out of a meeting with me to meet them, cast them in a different light.
So, I would be cordial and say that you’ll have to look at your schedule when you are settled at the new company, but don’t mention where or what you’re doing. Keep her at arm’s length, but don’t poison the well, since you may return to that company or know people in common if the industry is small.
