[Bug]: Routing and audio stutters in 15-20% of maneuvers

Nobody has claimed this yet.

### Mapbox Navigation SDK version

Main branch @2d71625 (324.18.0-beta.1)

### Steps to reproduce

I downloaded the current main branch and used a provided CarPlayExample app. When driving around the town, I noticed that in about 15-20% of the maneuvers, there's stuttering in voice instructions. It lasts just a few seconds, so I was not able to capture this (the voice is like "T-T-T-T-T-Turn right"), but in one case this effect was happening for about 30-40 seconds as I was waiting for the signal, and I was able to capture the screen:

https://github.com/user-attachments/assets/54cc92ac-fc3e-48f8-a134-e44e00f7e1cd

It started with voice stuttering as well, but after about 10 seconds it was just quietly recalculating the route.

I'm using iPhone 16 Pro Max with iOS 26, debug build.

### Expected behavior

No lags / no stutter; navigation is performed smoothly, without ghost rerouting attempts.

### Actual behavior

See above.

### Is this a one-time issue or a repeatable issue?

repeatable

Start by reproducing the stuttering and ghost rerouting in the provided CarPlayExample app from main branch @2d71625 on the reported iPhone and iOS version. Trace the voice-instruction and route-recalculation behavior during repeatable maneuvers; done means navigation proceeds smoothly without audio stutter or unintended rerouting.

Written by the indexing model from the issue text.