GH5 Stacking ND with IR filter - infront or behind a non IR ND filter?

[analogs]

Does it make a difference if you stack an ND filter with IR to a non IR ND filter behind or infront of it?

eg.
Lens > Benro Masters ND which has IR > Hoya Prond Filter
Lens > Hoya Prond Filter > Benro Masters ND which has IR

Do you need both filters to have IR in order for it to remove IR properly or does the IR reduction weaken? Eg. like placing a drop of food colouring into a cup of water vs into a litre of water.

I was informed that IR in NDs help reduce color shift, is this true for digital cameras like the Panasonic GH5, Canon 5D3, GoPro, Sony X3000 action cameras, G7XII compact cameras?

Thanks.

 

[Mitch Gross]

IR should always be the first thing light hits. This is because there can be reflections bounced off it and that would be problematic if there was another filter in front.