Hi Ben,
It is probably showing 4*8bit/channel. You can test this while rendering without alpha, if it shows 24bit then, you know. Typical nonsense that I can’t really understand, a leftover from the ‘80s.
For everyone reading along:
It is often used in printing. However, even the Radiance format is often WRONGLY expressed as 32bit. It is a 4*8bit as well (RGBE), just unusable inside of the production pipeline, to say the least. (“Manual, special 32-bit per pixel”, not per channel!)
Anyway, 8bit/channel, if used at all, should be considered only a final delivery format for absolute low-end production, like the web/preview, etc.. During production, the limitations of a gamma based (sRGB) 8bit/channel are just too large.
All the best
P.S.: PNG in Cinema 4d is either 8 or 16bit/channel
https://help.maxon.net/us/index.html#6198