text deleted when pressing 'a' key

This happens on Windows 10 PC. Sometimes something happens and then if i type letter 'a' into in-game chat it deletes all existing text and i am left with only a letter 'a'. In addition to that - backspace does not delete any text as well. It is unclear what causes this issue as it comes and goes. Usually issue manifests itself upon game start and goes away after 3-5 matches. When i am finally able to type letter 'a' without loosing any text - backspace starts to work as well.