This bug exists in the original version of wwwBASIC and continues to exist in the version of wwwBASIC embedded in BAM.
Although I was at first pretty horrified by this bug, I've come to the conclusion that it is not a devastating bug.
Two or more subroutines called at the same level (let's say called from the main part of the program and not from some subroutine or function), the variables of each subroutine share the same memory space as variables in other subroutines.
Nested subroutines (I.e. one subroutine calls another) do not share the same memory space.
However, when subroutine "A" calls subroutine "B" and subroutine "C", the two called subroutines ("B" and "C") share the same memory space because they are called at the same level.
The workaround: in subroutines and functions, initialize all declared variables to wipe out possibly existing data values in the related memory space.
Please review the following code and that code run with the original wwwBASIC: