Addresses disappearing in VCDS

[kzslt1]

Hi guys, I'm having some engine issues with my Leon 1M (1.4 AHW) and after completing the auto diagnostics in VCDS I noticed that some Addresses/controllers are not available any more. It managed to run the diagnostics only on Address 01: Engine, Address 15: Airbags and Address 46: Central Conv.
Few months ago Address 17: Instruments and Address 19: CAN Gateway were also available and tested, but not any more.

Any suggestions on this one?