Did something change in the control of the bit depth of textures on import between versions 2.1.0 and 2.1.1? It appears that in 2.1.1 when 16-bits is specified, all channels are exported as 16-bits even if there is only 8-bit data (e.g. base color RGB). 2.1.0, on the other hand, seemed to export 16-bits only if the channel was high dynamic range (e.g. height map or normal).
I prefer the previous behavior for economizing memory.