The hold function works a bit differently. The rearm option doesn't mean that it will reset the formula to a "default value" when the trigger is reached, it just means that the hold formula is ready to hold another value when it reaches the initial trigger. Until that happens, the formula will sit on the previous value.

For example if you use the following formula: hold(time,time>10,'Sine wave'>0), it will hold the signal value after the time reaches 10s. When sine will reaches 0, the formula will again start looking for the hold condition ('Sine wave' > 0.