Hi guys,
Sorry it took a while to give an update on this. Just so you know, Aliexpress had already resolved the captcha issue. This information has been confirmed by dropified's support team as well as Aliexpress' customer service. I haven't experience this issue for a few days now.
If you ever encounter this issue again(or still experiencing this issue) though, I recommend cooling off for about 15 mins, I haven't tried an interval lesser than this but you can try. I noticed that you can process a lot more orders without captchas after your first cool off. But increasing your "cool-down" interval won't let you process any more orders than if you cool off for 15 mins.
Happy Q4!