Crash while dodging Groak burrow swallow using Cannon

Using the Cannon dodge at the same time Groak burrowed out caused this crash:
[string "scripts/stategraphs/sg_player_cannon.lua"]:4078: attempt to compare number with nil
LUA ERROR stack traceback:
    scripts/scheduler.lua:155 in (method) Update (Lua) <145-208>
    scripts/update.lua:135 in () ? (Lua) <119-173>