The people here in the forum are not 'anyone at coffeecup', we are just users like yourself. We have seen, at times, that some anti virus or anti malware apps may interfere with the downloading or installation of CC software, but to my knowledge, we have never heard of any 'gremlins' changing or deleting code from the pages we make with that software.
When creating a library item you have two options: either you save
the selected code as... or you convert
the selected code to... If you choose the latter, those snippets are put in place as soon as you have clicked on 'create'. But that happens just on the page you have open while creating that snippet. Afterwards you need to go around to every page where you want to have the same library item and manually paste it. When that has been completed, next time, if you make a change to that item, you just do it once and then choose which of the three update options you want.