An uneven case run is information, not a nuisance. Gather the context before changing anything.
Note days since casing, because a bed on day 4 and a bed on day 8 are not the same problem. Measure casing depth at five points, since a thick patch simply takes longer. Read compost temperature as well as air, because the bed still runs above the room. Note where the slow area sits: near the door, under a vent, at one end of a rack. The same symptom from a different cause needs a different answer.