Thanks for the screenshots @roykela
So essentially the way it was last year with 'player instructions' was a bug, it was carrying across player instructions when it shouldn't have been - player instructions should only be applied to the specific game they are set for and then reset until you set them again, by position should always be carried over.
For example in the second screenshot you've attached - if those instructions were set BEFORE the match (so tight marking on the 2 CMs & ST, show on to weaker foot for DL/DR & ML/MR) they should stay until you change them (i.e. complete that match, carry on to the next and those instructions should be the same) and will apply to players in those positions in the next match.
By default when you go in to the tactics screen it shows the opposition instructions by player (the option on the right of the OI column), once you change that to 'by position' it should show your previously set instructions carrying over
Essentially if you're setting instructions by position then they are being remembered and applied (you can check this after a match by looking on 'tactics -> opposition instructions' and select 'by position' they'll still be the same) you just need to click the 'These instructions will apply to all players in this position' option to see them in match. I've asked the tooltips to be updated to better reflect that one is 'by position' and one is 'by player'
Hope this makes sense, any other questions let me know