i think it may be a colliders thing, always happens when you change characters just disable it in kkpe advanced mode having the collider selected
Search collider in workspace, open the folder of the chara and select bone collider
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Now open kkpe options and click adv.mode
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this window will pop up and just click "all off" search penis7 section and mark penis01 02 and 03
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Advice: you may want to check this before you change characters bcs sometimes in other scenes people use it for something else, so you may want to check the advance window and see what is marked and what is not, i think that the majority and Hong cha generally use it just for the penis direction so doin "all off" and marking the penis bones is enough.
sorry for grammatical errors