I think there is probably more than one bug being discussed here.
There are two bugs that I experience consistently on my iPad in Apple's Notes and Mail apps, and in the Ulysses app that I have used for a couple of years for writing. These bugs also show up in the same apps on my Mac.
The first is that after a while, the dictation will simply stop working for more than one sentence or phrase at a time. If you get to a point where you have to pause, it will not continue after that without the app being restarted.
The second one is what I call a showstopper. Dictating text and then touching the undo icon at the top left corner of the keyboard will crash the apps instantly. I can do this at will easily. I’m certain that it is a system problem. It’s been around for a couple of years in versions 17 and 18 of iPadOS.
There is a third bug which I’ve seen other people describe here as well but I’ve only experienced once. Basically, dictation simply doesn’t work in some situation that I haven’t been able to pin down. Most of the time, including for this post which I’m also dictating, dictation works well enough for me to use extensively in all the writing I do. I’m aware of the bugs and I know how to work around them until they get fixed.
The complexity of dictation software is beyond me. I don’t think I can even imagine how complex it is. The fact that it works as well as it does still amazes me. I remember what dictation was like 30 years ago in the 1990s and compared to that, this is wonderful. So I’m willing to put up with the bugs and work around them but I’d love it if they could be fixed.
just to point out, this whole post was dictated in around five minutes with no interruptions or problems on my iPad Air running the most current version of iPadOS 18.4.