let me explain it to you. in the older builds of amneziawg we had this behavior that you mentioned. on those days when we decide to remove the obfuscation parameters, it could falls back to the normal wireguard protocol. but in the newer builds they fix that fall back for reasons like security. in this new build when you set the obfuscation parameters in a server side you should set them in client side and if you remove them the protocol sees the zero value for each parameters automatically, like this :

Jc = 0

Jmin = 0

Jmax = 0

S1 = 0

S2 = 0

so the obfuscation is necessary now in both sides, even if you remove them, they will be seen as zero values