Somewhere on the hp65 owner's handbook it stats that when starting program execution from the keyboard pressing [R/S], the first [RTN] is ignored by the calculator and it stops at the second [RTN] found. That's true, but it seems not only the first [RTN] is ignored, also every [g][NOP] instruction found till the second [RTN].
If you try the following program (clear memory first):
LBL A_
5_
RTN_
2_
g NOP_
+_
RTN
Pressing [A] will leave the answer 5, pressing [GTO][A] and then [R/S] will leave 7!
If you try this other program (clear memory first):
LBL A_
1_
RTN
Switch to RUN mode and press [GTO][A] and [R/S]. The calculator passes through A and all following [g][NOP] steps on memory, back to top of memory and stops at [RTN]. If you look the stack contents the number 1 is on both X and Y registers (A has been executed two times).
Supose I'm the LAST one who discovers this...