I decided to shoot a short sequel to my GH4 VLog video "Chicago." Recorded internal at 8 bit on the GH5. Handheld with IBIS. V Log L.
I don't think it is IBIS faulty IMHO, but certain 2x anamorphics coupled as far as I've seen since the early footage going along from there.
Take a look on the adapter 40 compact 1.33x version instead.
I guess Jurek, the shooter had used IBIS and does really help without any wobble distortion at all: https://vimeo.com/user2020056