Creating a new term equal to an existing synonym overwrites the parent term

If you create a new term with the same name as an existing synonym, it will overwrite the parent term of that synonym with the values from the new term form. This will most likely include erasing any other existing synonyms of the parent term (since the Synonyms field of the new term will probably be blank). This kind of unintentional data loss seems very bad to me.

I can't tell from the parent issue, #1948508, if this was introduced by that fix, or if it was a pre-existing problem. There is some suggested code in there that may provide a fix.