Well, mostly it is training issue of the lounge dragons.
I remember cases with my OK+ Gold card in few lounges, after they had changed the design of their cards (twice in the last 7 years). I remember once the situation in Singapore, where the lounge dragon said that I can't enter as my card does not look exactly like the OK+ Gold card in her manual and she showed me the printout of the old version of the card. After some more arguments, she finally understood that I'm OK to enter (and have my shower).
But sometimes not only lounge-access, but other perks can be denied too. Once in JFK when checkin in for KLM flight they did not want to let me to access the business class check-in desk and reroute me to very-very long economy line, saying that other than KL Elite Plus members are not allowed to do so.
So, to avoid misunderstandings, I always keep printout of my rights with me, so that when needed, I could show and train the staff myself
And that is for free of charge!