Technical Reverse popping out M32

[roll]

Hi, I have bought “new” Bravo and it has problem with gearbox. I can shift every gear with no problem, there is no noise or shifter movement, so bearnings should be fine. But when I want to put it in reverse, the shifer does not hold in, it pops out when I release the clutch.
Any tips? Can this be repaired without rebuild?

Thanks