As identified and described in [RedGrittyBrick's answer](https://skeptics.stackexchange.com/a/57135/61552) via [AnUnearthlyGay's reddit post](https://www.reddit.com/r/transformers/comments/1dz3tir/the_response_i_got_from_the_bbc_for_a_complain_i/) this was [claimed by the BBC](https://i.imgur.com/GK73GbU.png) to be a response to a difference in definition of "non-binary" between that given in the original episode and "the accuracy of language we need for our young audience".  Comparing the language used, which defines non-binary simply as "People who aren't female or male" to the complexity of the definition given in their guide for parents (quoted in the other answer) perhaps gives an idea of what they are talking about.

I include my older answer below, mostly to provide some evidence it happened.  I think it adds little given the BBC's response.

It is definitely true that the original includes a scene that has been indelicately removed from the version currently available on the BBC.  [This episode is available here in the UK](https://www.bbc.co.uk/iplayer/episode/p0g9f9cn/transformers-earthspark-series-1-17-home-part-1), one can skip to 10:30.  It is quite jarring; the background music also cuts out for a second after the words "my friends" and then returns with the next scene.

The presence of a missing conversation is confirmed in the [subtitles available here](https://www.opensubtitles.com/en/subtitles/9499799-transformers-earthspark-s01e17e18-home-pt-1-and-pt-2-1080p-pmtp-web-dl-ddp5-1-x264-whitehat).

> or other non-binary people.
> 
> Non-binary?
> 
> People who aren't female or male.
> 
> Oh, I'm sorry. I shouldn't have assumed.
> 
> I always knew my pronouns felt right, but what a wonderful word for a wonderful experience.

[This season was first broadcast](https://advanced-television.com/2023/07/20/transformers-earthspark-on-cbbc-iplayer/) on July 25th 2023, starting with the first 10 episodes, this is episode 17 so would be expected some time after that.  [In May 2023](https://www.newsweek.com/transformers-non-binary-pronouns-lgbtq-transgender-1800099) this story line caused controversy in the United States.  It is plausible this cut was not made by the BBC, and I have not found confirmation one way or another.