Robert Charles Anderson in The Great Migration begins Vol 1 p 90 (Edward Bangs) writes:
"Citing a supposed entry in the Hobart diary, Mary Walton Farris suggested that Rebecca was daughter of Edward Hobart of Hingham, but this entry may not have existed, and the identity of Rebecca (___) Bangs remains unknown [NEHGR 121:4, 56]."
Anderson is referring to Dawes-Gates Vol 2 page 61 which is available on Ancestry.com.
Mary Walton Farris was an excellent genealogist but as Anderson points out in NEHGR 121:4,56 they review Peter Hobart's journal and find no such entry and therefore find her claim unfounded.[1]
From https://www.wikitree.com/wiki/Unknown-342944
A more detailed description of the dispute mentioned by Anderson:
Ferris[2] mentions in a footnote that "the assertion has been made" that a diary of Rev. Peter (Hobart) had an entry regarding a trip to attend the funeral of "sister Bangs." Egan[3] states, regarding a journal, likely written partially, or even in entirety[4], by Rev. Peter Hobart's son Deacon Dave Hobart, that "No such reference [to that trip] is found," Egan does allow that Ferris' statement of "sister Bangs" may indicate access to Peter Hobart's original journal and an omission by Dea. David Hobart in the journal of that article. An Editor[5] of the NEHGR, later in the same volume, clarifies and reiterates that the "original" diary (in the possession of the Massachusetts History Society) appears to be "almost entirely" in the hand of Dea. David Hobart; and perhaps there was an original diary from which Davd Hobart extracted information.
Other information: the dispute regarding Rebecca's parentage apparently results from the following items:
Rev. Peter Hobart had a sister Rebecca. This is established elsewhere and doesn't appear to be disputed. A diary of Rev. Peter Hobart is mentioned[6][7][8][9] in which the author(s) describe an entry by Rev. Hobart, he taking a trip to attend the funeral of "sister Bangs."
It is unclear[10] whether the phrase "sister Bangs" was intended to indicate a biological relationship, or a member of Rev. Hobart's congregation. I.e., records by clergy often refer to the "Brethren" of their congregations, referring to individuals as "Brother" and "Sister."
Edward and Rebecca Bangs had a grandson named Hubbard Bangs; "Hubbard" may be a variant[11] of "Hubbert, Hobart."; the grandson's name may be an indication of his grandmother's maiden name.
Observation[12][13]: Rebecca Hobart had siblings named Sarah and Joshua. Edward and Rebecca Bangs had children named Sarah and Joshua. It is not uncommon that names reappear in later generations of a family.
Mentioned in some of the references (including Anderson: "No further information."), there appear to be no records or mentions for Rebecca Hobart after about 1635. The implication is: if she was not the wife of Edward Bangs, what happened to her?
Unfortunately, the argument that Edward's wife Rebecca was Rebecca Hobart, sister of Rev. Peter Hobart, is circumstantial. Whether the diary entry, or the diary itself, existed, is moot, as such an entry could be argued to refer to a "Sister" of the congregation, a common occurrence. The observations may appear compelling, but, as observed by Anderson, her identity must remain unknown.