Dots switch position when changing data and value props sequentially

[BobToninho]

Describe the bug

When updating the data and the value props sequentially, the slider breaks inverting the second and the third dot.

Repro: https://jsfiddle.net/thetoninho/f2cq67rg/16/

Steps:

1. Open the repro
2. Open the console
3. Run test() in the console
4. You should see the second and the third dot inverting

Environment (If you feel unrelated, please delete the block)

• Vue version: tested on 2.5.2 (repro) and 2.6.12
• Component Version: 3.2.15