I'm not sure why she's doing this but I think it's probably due to her getting more comfortable at the canter and more balanced so now the canter, instead of being an awkward unbalanced gait that she does rarely, is a comfortable "one of the girls" for her, if that makes sense.
Anyway, today we were cantering along, I had picked up contact (thank goodness!), and Lacey decides that this log is out to MURDER her. She immediately ducked out to the opposite side of the trail and continued to canter (kinda proud of her for that! Usually she'll take any excuse to fall out). I had her stop and we went back and trotted past that log again just so she could see that it really wasn't as evil as she thought. Of course, she didn't spook a second time, just trotted along like NBD.
In any case, that ducking over she did was some pretty skilled work and something I was totally unprepared for. I stayed on relatively easily but if she had ducked any harder, my status on her back would have been a little bit more iffy.
My automatic thought response to this is that as soon as she started kinda looking at that log, I should have possibly taken up more contact with (the spook was towards the left, the log was on the right) with the right rein and put my left leg on with some feeling behind it.
^^Yes? No? If no, what should one do in that circumstance?