I bought an IZH-94 in 12/6.5x55 back in 2000. It was a heavy POS with a rifle barrel that shot patterns, not groups. Mine had a shotgun barrel with a fixed choke that seemed to be in the modified to full range and the center of the pattern was 10 o'clock high and left. My IZH-94 was a poster child for anyone who believes that cheap combination guns suck.
I sold it to a friend who was convinced that he could make it a shooter, but after a year and a pile of rounds fired he gave up on it. He offered to sell it back to me for $200. I declined, but given what people are willing to pay for them now, I probably should have paid the $200. Maybe I should call him and see if he still has it for sale.
My 12ga 7X57R shot great. The triggers on most combo guns without set triggers are generally bad for rifle shooting, even on pedigree makers' guns.
As to the shotgun and rifle not shooting together, the Bikals can be regulated, or at least mine could, to shoot together. The shotgun can be zeroed to the sights, then regulate the rifle to come in to the POA.
The Baikals no doubt have lemons among the ranks. They no doubt have some quality control issues. The Savage 24s suffer this, but they can't be easily regulated.
