The history as far as I understand it.
ntp was requested to be a synonym by a senior member of the Ask Ubuntu community (no names required to be mentioned).
Yesterday, another similar synonym creation question was requested and was granted.
At the same time a number of outstanding synonyms that were requested by other senior members for quite a considerable amount of time were actioned which included ntp --> time.
This particular request was revoked today by an AU mod - probably after reading this Q&A and acting on the relatively high number upvotes given to a AU meta question.
The history link you have given is for edits to the tag - not for synonym creation. Looks like no actual history is recorded for these.
There are a number of outstanding synonym requests - for those in the community with high enough rep - please review these and either upvote or downvote the requests. Thanks.