So why did she do it?

Re: So why did she do it?

OP your MIL’s behaviour is very confusing. I cannot think of why she would do this but good on you for handling it well. Don’t dwell on it much, her motives will probably never be understood and the main thing is that your husband understands what happens and is aware. Don’t worry about anything else and maybe just be on your toes the next time she comes and visits.