this bug is very straight forward and i can’t believe no one has made a report yet despite how commonplace it is.
basically, unless the belt is EQUIPPED PRIOR to entering spriggan form, the belt does nothing, EVEN after putting it back on again.
for example, i put on any other belt that’s NOT legacy of the quiet forest OR no belt on, enter spriggan form, my rage degens as normal, if i put legacy back on, the game doesn’t register the new belt effects, and rage does NOT regen every 3 seconds, i’ve tested this over 30 times and have pinpointed it to this exact cause.