The null revision created in the page history for moves has always been minor since null revisions for moves were added in 2005 (rSVN7964: Decouple revision.rev_id from text.old_id). There was an attempt to change it in 2009 (rSVN45788: Page moves should not be minor edits), but that was quickly reverted (rSVN45938: Revert r45788 "Page moves should not be minor edits").

Further, according to api.log there was nothing in Framabot's call to API action=move that attempted to set it as minor. Which is to be expected since there is no flag defined in ApiMove for that purpose, nor does any of the underlying MediaWiki code in this code path seem to access the request directly.

2017-09-16 17:37:38 [Wb1hXQpAEDcAAF2QVAgAAAAX] mw1290 frwiki 1.30.0-wmf.18 api INFO: API POST Framabot <REDACTED> T=4678ms action=move format=json maxlag=30 assert=user from=Cat%C3%A9gorie:Mod%C3%A8le%20politique%20de%20l%27Islande to=Cat%C3%A9gorie:Mod%C3%A8le%20politique%20en%20Islande reason=%5B%5BWP:RBOT%5D%5D movetalk= noredirect= token=<REDACTED>