It is mate I know for a fact that any any Cumbria team that runs a 1st and 2nd have a rule that they can only play 4 players who have played 5 or more games more the 1st team.
I know the lad who runs the Egremont A team and they follow that rule for years, The same lad also plays missed out on playing in a final few years ago as due to this rule he had been in the 1st team for 6 games all off the bench on away and played more A team games than 1st. it’s not new and it’s not directed at NCL players, The likes of Elbra, & Cockermouth will also fall under the same rule with there A teams and there not NCL.