What is the chance that the ammonia itself would damage parts of the computer? Surely few, if any machines are rated to deal with liquid ammonia immersion with direct PCB contact.

Also, afaik Ammonia dissolves zinc into zinc hydroxide, which is a semiconductor, and liquid ammonia may also be electrically conductive even if gaseous ammonia is not. There's so many things that could go wrong with that in my mind, but I would really like to know where you heard about this or if you're doing work with this somehow and fill in my own knowledge gaps if you will.