Apple Watch 9 (A2978) automatically adding numbers on lock screen

When trying to tap to open my Apple Watch 9, the unlock passcode screen was displayed with random numbers being automatically selected. This happened several times, I could not stop it without placing on power source and hard resetting.

This is the first time this has happened.

The two green backlights (wrist monitors?) were also flashing as the numbers were auto-selected. The result was I had to wait 1 min to re-enter passcode. I did not wait and forced power off after placing on power.

This happened whilst originally on my wrist, when I had removed and wiped both sides, and continued when on power.

No protective screen was attached. I do not wear my watch in shower and have not yet submersed in water.

Anyone else have this issue?

Any suggestions to cause?

Thanks for your help.