Yes, so I see others are experiencing the same thing on their Samsung Galaxy S6's. The EN keyboard/auto-correct worked fine for years, but then recently it really began to go haywire repeating symbols and letters that I'm not even typing, auto-correcting in a weird manner, etc. It can be really frustrating and it continues to do this even when I shut off auto-correct.
On my Mac I access EN through the Google Chrome browser and it works perfectly, but even shutting off auto-correct on my Galaxy S6 doesn't change the dysfunction.
I'll stay tuned here in the hopes this gets resolved soon. I've always loved the app, but this makes my note-taking problematic, which is very important for me.