Yes, this is known problem and can happen also with HID keyboards. Unwanted key repeat is caused by key release event received too late so the autorepeat feature of linux kernel kicks in since it thinks key is still down. Can be related to high CPU usage on tablet or 'noisy' environment on bluetooth/wi-fi frequencies or maybe low batteries or maybe even specific keyboard model with poor bluetooth implementation. Can be also poor bluetooth implementation in linux kernel. Hwever completely lost keys should not happen, only key events received late.

This issue can be partially fixed by raising kbdd priority (in case of high CPU usage) or changing key repeat rate. Happened to me few times. Recently it seems to work fine but I'm not using the keyboard so much. Sadly there is nothing that can be done in kbdd to solve this.