Very interesting.

That said, I still think it looks suspicious - here's why. I don't think anyone at 25NL is balancing their range in this way.

I think it may happen the other way around, like if I spike a set on a 2-tone board and I'm heads up with an aggressive player I'm going to raise hoping for him to think I have a draw, but I don't think anyone is flatting a draw in order not to look too much like a draw.

I definitely think that lots of 25NL players are going to realise that a raise on Jx5d2d is quite likely to be a flush draw, but I don't think that leads to the adjustment you talked about of flatting flush draws because there are more of them than legit monsters.

If people are flatting with flush draws at 25NL, I think it's much more often because they are passive and that's just what they do, rather than it being any kind of adjustment.

All that said, this is an interesting discussion - it's nice to unexpectedly get into a discussion of this kind of stuff (balancing ranges) when dissecting this hand, as it's not something I have reached the stage of thinking about yet, at least not to the extent you're talking about.