Function uses global variable causes inconsistency in variable id

Example:

<?php
$global = "B";
function TestTaintOnFunction() {
    global $global;
    $secondVar = "2";
    echo $global;
}

Results in:

    Expr_Assign
        var: Var#1<$global>
        expr: LITERAL('B')
        result: Var#2
    Stmt_Function<TestTaintOnFunction>

Function TestTaintOnFunction():
Block#1
    Terminal_GlobalVar
        var: LITERAL('global')
    Expr_Assign
        var: Var#1<$secondVar>
        expr: LITERAL('2')
        result: Var#2
    Terminal_Echo
        expr: Var#3<$global>

Anyway to make the id consistent?

Reproduce the issue with the TestTaintOnFunction example and compare the generated control-flow graph for the global assignment, the function's global variable, and the echo expression. Trace how variable IDs are assigned across those entries; done means the same variable is represented consistently wherever $global is referenced.