Not quite the same thing, but relatively similar. It irks me to no end when I ask a question that has some (either explicitly stated or—at least I thought—implicitly stated) elements that I understand. And then people answer the question by re-explaining the thing that I already understand.

This one doesn't bother me as much most of the time. Some people brains work differently and what you're describing I've seen with two different thinking patterns:

1. The person is "showing their work" to make sure you both agree with the premise and supporting arguments.
2. The person is actively thinking through it out loud as a method to process your question.

However, if they get to the end of their re-explaining, and still haven't answered your initial question, then they can be pressed or guided into it. Sometimes you have to give an obvious wrong answer for them to contradict. "So are you saying the observer experiences no elapsed time relative to the traveler at the speed of light?"

I like to think it lets them know “hey, this person thinks they’re helping even though they aren’t directly answering, but feel free to ignore it or clarify if they’ve made a mistake”.

I try to accomplish the same thing by just giving them the explicit answer they asked for up front.