Yes, That is correct. There are several feature requests to make this behaviour more consistent so that it is possible also to edit the titles of multi-part works. A common use case would be for transcriptions where the instrumentation has changed and the canonical titles no longer make any sense.
I have maintained my titles with the original title (intended by the composer). In this case the title of this composition should be:
Sonate Nr. 1 f-Moll Op. 2 Nr. 1
Roon is not using the composition titles as originally published. With major composers I wouldn’t have thought many were, especially those that have been catalogued, sometimes several times. Instead roon is using canonical titles devised by its metadata supplier Tivo/Allmusic. You can usually see what those are on the allmusic.com site.
If you consistently apply these canonical titles, the advantage is that roon can identify at a composition level (not just album) and group together all your performances of a composition, regardless of who the performer was or which album release or compilation box-set they appear on.
If you really want to use your own titles, you will then have to “un-identify” them, usually by un-identifying the album. But then you will lose much of the value of roon as a Classical music organiser. But you may still prefer that as roon also gives you ease of physical networking of audio devices.