Function body does not get properly reduced

[Ehcsan]

When running (for example) Slicing/Static Program Slices/Calls/Using strings for definitions the function body does not get reduced properly.

some nodes selected //call to reconstruct ExprList hass only some nodes selected
5
some nodes selected //call to reconstruct ExprList hass only some nodes selected
a <- function() { x <- 3; 5 }
a()
got: //output of the test
a <- function() { x <- 3; 5 }
a()
vs. expected:
a <- function() { 5 }
a()