I just downloaded the new firmware upgrade a few days ago and I'm having the same issue. I have contacted the Arturia Support team and I am currently waiting on a response. For now, I have the arm to clock set to on and I have found a "workaround" by setting the toggle switch to arp mode, pressing play on the keystep, then bringing in the Keystep sequence by flipping the toggle switch up to seq mode. This will always start the keystep sequence on step one. So, for me, it's a matter of using the toggle switch now to bring in my sequences when I want, and they only way I know of (for now) to make sure the seq always starts on step one. Let me know if this helps you or if you have managed to figure anything else out. Thanks!