This a list of known DCC control equipment that has been found to have problems programming/controlling the MTH Protosound 3 engines/boards. (Some DCC equipment can have problems programing certain DCC decoders so this is not something isolated to the MTH Protosound 3 boards.)
Problem DCC equipment list: (when trying to program MTH Protosound 3 boards/decoders)
Marklin Central Station 2 (aka CS2):
Reported issue with PS3: Has problem programming/changing CV values on some boards.
Reported issue with other non-MTH DCC decoders: Has problems programming older/early Marklin decoders
If you have issues, please review this master reference page: https://www.mthtrains.com/service-documents-taxonomy/proto-sound-30
Also for NCE, see: http://www.rayman4449.com/Programming_The_NCE_DCC_Controller.pdf
I maintain DCC related info on my website at: http://www.rayman4449.com/DCS_Overview_Videos.htm#Operating_PS3_Under_DCC