I think a lot of it is down to the silver prism coatings used in many roof prism binoculars of the HG-L's vintage. I see this in eg. my P model 10x40 Dialyt, Swarovski 8x30 SLC mark II etc. I definitely think that the move to dielectric coatings (all those recommended to you - Leica, Zeiss Victory Pockets, Swarovski CL - have these), besides improving light transmission, also resulted in greater colour fidelity.
I've found that slight yellow cast (and it is in most cases quite slight) to make itself most obvious against white backgrounds eg. bright white clouds. When it's grey and murky (unfortunately often the case in UK) the slight yellow cast on top of those conditions can seem particularly displeasing. But against foliage etc. it's much less noticeable and may in some cases offer slightly more contrast. The yellower light of mid to late afternoon matches that type of colour rendition very well. At that time of the day, perceived image quality (to me anyway) is at its best.