First_path_idx wrong when disable dgc and read cir

Hello I try to disable the dgc by using preamble code out of range 9-24 and i seems to be working fine (are there some other ways to disable the dgc?). But when i read the cir with first_path_idx I don’t get the real first_path in the cir its somewhere else inside the cir and jumping around. I’m using the <dw3xxx_xr6.0c_24FEB2022. zip>.
I want to read the cir without the dgc (dgc disabled) with a near stable first_path_idx.