I figure you are going to decode this with CodeX? I did that just now (first time I've done this) and nothing is standing out to me that would make it pause at the end of the first layer for 4 seconds.
Yes. You are right. There's no pause in the codefile.
Also, does the 2nd gen Cube really heat the extruder nozzle at 250 C for PLA?
Yes, but only for the first layer.
Second layer works with 235 C.
May be your Cube is waiting until the 235 C is reached?