This can happen when your constitution is fluctuating over the threshold.
If you are exhausted, then rage up over that point, and the exhaustion ticks below what the threshold was before, then when rage ends since the check for going from a point higher than the threshold to lower than it was never done it doesn't register that exhaustion needed to be removed.
24 threshold, 27 points at exhausted, rage over that 27 points to a higher threshold, if the exhaustion points drop below 24 before rage ends it'll be stuck.
But yes resting is the way to fix it.