Imo the difference between the two examples you posted is board texture.
A shorties min-raise on a low board (one likely to have missed the preflop raiser) is more often a bluff.
A shorties min-raise on a board likely to have hit the pre-flop raiser
such as JQK board is like a 'value bet' for them.
(They want to get more money in the pot or induce a shove but can't 3 bet properly because they would be devestated if you folded.)

(Though a shorties flop lead into the pfr is still generally a sign of weakness/mediocre hand regardless of texture.)