I’ve been noticing this quite often.
I was just trying to edit a post and when I opened it, clicked with my mouse in a certain place, started typing, and suddenly the text cursor jumped to the very end of the post.
Example: let’s say I have this as a reply that was already posts:
Aute aliqua ea elit ad ut dolore qui commodo. Veniam est consectetur dolor in adipisicing duis nisi ipsum incididunt nostrud labore officia anim Lorem. Aute quis commodo officia est occaecat ex amet. Ea minim laborum commodo in adipisicing quis officia non exercitation sunt velit aliqua laborum qui veniam. Dolor laboris reprehenderit occaecat consectetur enim tempor. Minim amet incididunt culpa commodo anim.
Now, if I want to edit it, I click the pencil and place the text cursor where the 
is, and I start typing. A few characters in, and it jumps to where the 
is.
Aute aliqua ea elit ad ut dolore qui commodo. Veniam est consectetur dolor in adipisicing duis nisi ipsum incididunt nostrud labore officia anim Lorem. Aute quis commodo officia est 🛑 occaecat ex amet. Ea minim laborum commodo in adipisicing quis officia non exercitation sunt velit aliqua laborum qui veniam. Dolor laboris reprehenderit occaecat consectetur enim tempor. Minim amet incididunt culpa commodo anim.✅
So basically some characters are typed where is and the rest where is.
Hope it makes sense what I’m experiencing.
Just to be clear, I believe this is only happening here on the Discourse forum. I haven’t been using my own forum that much to write topics yet, so I can’t confirm. And it doesn’t happen every single time, but I decided to report this.