The tricky thing with Hermes is that they either
Do not provide a detailed description - the older ones from the 1980s - are marked carré in catalogs, the fact that they are not twill is not mentioned
Or, change the weight of a given fabric ie twill has come in many weights over the years - I probably have a dozen different 90cm twill weight fabrics - but , of course, I am into the oldies , these are better standardized now
Or, worse yet, they use some (supposedly) useful term in a loosy-goosy fashion. Mousseline, chiffon, voile are used on the web sites to refer to a variety of weaves and fabric blends (cotton, silk/cotton, CS/silk). Even the recent Nepalese CS blends are called mousses at times
In a nutshell, Hermes-speak is not an exact language. Same thing applies to size - is a gavroche 18 in or 45 cm ?