delayed freeze after each round

[off-by-zero-error]

after playing a round at any level, the interface will work for a few seconds, then freeze for about ten seconds. if a new game has been started then the balls begin moving normally but ignore all touches. the touches seem to be stored and applied all at once, so each ball is suddenly moving at the combined vector of all it's touches.

this game is still playable if i wait ten seconds on menu screen before starting a new round. sorry to be bringing an issue to a perfectly clean git.

i'm using this on a moto g with android 10.