Chicago-style bibliography ignores the volume and subtitle

[Omikhleia]

SILE 0.14.17 or 0.15-develop

Example:

@book{DragonDeBrume1,
  title     = "Tolkien, le façonnement d'un monde",
  subtitle  = "Botanique & Astronomie",
  publisher = "Le Dragon de Brume",
  year      = 2011,
  volume    = 1,
  number    = 2,
}

Obtained reference: Tolkien, le façonnement d'un monde. Le Dragon de Brume, 2011.

Expected reference: Tolkien, le façonnement d'un monde. Vol. 2, Botanique & Astronomie. Le Dragon de Brume, 2011.

From template:
Author Surname, First Name. Book Title: Subtitle of Book. Vol. #, Title of Volume. Edited by First Name Surname. Place of Publication: Publisher, Year.

See also https://libguides.tru.ca/chicago/books-multivolume

N.B. Additional subtleties appear here, whether one should use title/subtitle or (rather) maintitle/title -- Our support is currently fairly limited. But the important thing here is to get something correctly identifying the work.
I'd be equally satisfied with Tolkien, le façonnement d'un monde: Botanique & Astronomie. Vol. 2._ Le Dragon de Brume, 2011 (which is what we'd likely get with title/subtitle, the devil is in the details...)