minecart stops before last active powered rail & can't get out of portal

https://youtu.be/7v8OjtEc-RU
I've made video report for better understanding.
1st issue is about frame drop while teleporting to other dimension. Frames drop so badly i can't even see direction or move away from portal and i keep teleporting.
2nd issue is about riding minecart. It stops at some points, probably at last powered rail just before station, but in reality after i rejoin i find myself at the end of path.