Let me guess, you did a TextField, not a CupertinoTextField? (It's 20% on release for me, still too much for a blinking cursor). Sure there may be some simple pathological bug in that one widget, but this quality issue in a fundamental widget in the official kit just does not give me the warm fuzzies, especially looking over the the github issue tracker.

And yes I am biased because it is google and they hardly dog food this product.

This particular problem is "fixed" by a simple cursorOpacityAnimates: false (which is apparently how they "fixed" TextField). That still doesn't speak well for QA. This is not really a complaint about a single widget. I really really want to like this stuff, but I have no confidence in it as a serious long term product.

https://github.com/flutter/flutter/pull/104335

Simple CupertinoTextField