Looks like the behavior changed since the last time I looked at it too. This is concerning when the reset timer resets. This is found in the function that's run when the command is executed. I started digging when I didn't see anything referring to the reset timer in the event handler or any of the functions it calls.
Lua Code:
-- Reset the timeout each time the sequence is used
local timeout = strmatch(entry.reset, "(%d+)");
if ( timeout ) then
entry.timeout = CastSequenceManager.elapsed + tonumber(timeout);
end
ChatFrame.lua:993