Small 4-Bets

[Our House]

I've been away for a while and really want to know...

What is up with these TAGs making tiny 4-bets in 2/4 NL??

So many players are raising my $46, $48, and $50 3-bets to anywhere between $100 and $120. Is there some kind of strategy behind this (maybe leaving room to fold to a push?) or is it just a trend? All I know is that they're getting owned pretty hard.

I'm genuinely confused.