I've recently noticed a friend of mine doing this.
She was having a Tupperware party, but cancelled the morning it was supposed to be on, saying that her hubby had a migrane and wanted everyone out the house. All good, but a week later she asked if I was going to the rescheduled one and I said I didn't know it had been rescheduled and she said that she had to because her DD was violently sick the day of the original one. I was going to call her out on it but couldn't really be bothered. I just can't figure out why she would lie about something like that.
There are a few other things, too. I'm just distancing myself.