No. GR (and other creative controllers on various STs) have always maintained that each script is considered on its own merits, and if tinkering with previously established events/characters/tech makes a new script better, then that adjustment is made. eg. Spock claimed he had a human ancestor. The next year, we discovered it was his mother! Ancestor? "Journey to Babel" was a better script by ignoring the previous comment, even though it was still true, if not bizarre.
The writers of screen ST do not have to follow any law or directive about contradictions. Aired ST is filled with contradictions.
ST licensed tie-ins should not contradict canonical events at the time they are written/published.
The only reason canon was ever discussed with ST fans (at conventions where GR was appearing, and in Richard Arnold's column in "ST Communicator") was to stop them complaining when and if screened Star Trek was seemingly ignoring events/characters/tech that had been presented in a licensed tie-in.
If individual screenwriters want to reference something from a licensed tie-in they can, but they don't have to read them, know about them, or answer to them. Licensed tie-ins do not inform the parent series. After all, they're read by only 1% of the audience.
In the proposal vetting stage, and at the final manuscript vetting stage, the staff at CBS Consumer Products are sometimes again allowing the licensed tie-ins to refer to each other again, and to TAS. This more relaxed attitude has existed since GR's death in 1991. The memo that was issued by GR's then-ST Office (after the new licensing contracts in early 1989) had specifically quashed such attempts because it was felt, at the time, that some licensed tie-ins were departing too much from the parent series. There was a renewed insistence that TOS tie-ins be about "the big seven" TOS characters, and that TNG tie-ins be about the then-"big eight".
During the time of Richard Arnold's employment at Paramount (official title: ST Archivist), all ST licencees had to have their proposals and final manuscripts vetted by both Paula Block's Office (at then-Viacom/Paramount Consumer Products) and the Star Trek Office of GR (ie. Richard Arnold).
The success of book series such as "New Frontier", which has hardly any TNG characters in it, has enabled the licencess to push the envelope more and more. "New Frontier" would never have been approved in 1989-1991.
Paula Block, who only recently left her post at CBS Consumer Products, is a member of "first fandom". So is Margaret Clark, editor at Pocket Books. Each licensed tie-in in considered by CBS Consumer Products on a case by case basis as to what references will or won't be allowed. As fans and professionals in their fields, they are usually pretty good judges on what works.
