Bug Running Program by Name

I save a program in a variable, ie 'ABC'. The program runs perfectly if:

a)- I tap on the EVAL KEY with the program on the STACK.
b)- I tap on the USER KEY which is assigned to ABC.
c)- I tap on the ENTER KEY after ABC has been writen on the command line.

But if:

d)- I put 'ABC' (with the quotes) in the STACK and I tap EVAL, then the program runs normally, but when it ends, Halcyon Calc stops running and closes.

The same happens if is a program which puts the quoted variable in the stack and then executes EVAL.

e)- I tap on the EVAL KEY after ABC has been writen on the command line, then the program hangs.

In a HP48SX calculator all five methods run fine.