This seems to be a hardware related problem occurring only on some Android phones. We are running an inquiry among all users who have reported this problem. Since we have trouble reproducing it could you please answer these questions and send them to firstname.lastname@example.org?
- What brand is your phone?
- What model is your phone?
- What is the version of your phone's operating system?
- What is the version of your Braintoss (see About in Settings)?
- Does the slowing down appear in every Braintoss or sporadically?
- Does the slowing down appear in the app (see History) or only after sending?