For dogs who have trouble organizing their body to enter weave poles at speed, here are some problem solving techniques to play with. Keep in mind you don’t have to set up all 12 poles to work entries, I often use 4 poles.
When you are practicing weaves, try to make it a game to stay in the poles. The more outlandish you can be, the more your dog can generalize that when weird things happen - it is time to knuckle down and concentrate. You need to set your dog up so they don't rehearse a lot of failures - either by designing your training session to build from relatively easy to challenging, or by using training aides.