Get two different result with two wroten way: strange with getAttr

GSQL Queries
1

I am using GSQL to write a algorithm, whose funcion is when given some attribute name(parameter features) of one type vertex, it will return sgc(short for simple graph convolution) feature of the given node.

If I use the flowing code, when the input set features = {“age”}, its output of @@sgc_feature is 2, which is wrong.

CREATE DISTRIBUTED QUERY tg_sgc_v1(VERTEX<some_phone> seed, STRING feature, SET<STRING> features,
                                   STRING v_type, STRING e_type
                                  ) FOR GRAPH SomeGraph SYNTAX V1{ 
                                
                                                         
    MapAccum<STRING, FLOAT> @@sgc_feature;
                                    
    start = {seed};                      
    FOREACH f_ in features DO
        STRING f = f_;
        neighbor = SELECT t
               FROM start:s -(e_type:e)- v_type:t
               ACCUM
                   @@sgc_feature += (f -> t.getAttr(f, "FLOAT") / (sqrt(s.outdegree(e_type) + 1) * sqrt(t.outdegree(e_type) + 1)))               
               POST-ACCUM
                   @@sgc_feature += (f -> s.getAttr(f, "FLOAT") / (s.outdegree(e_type) + 1));                     
    END;                              
    PRINT @@sgc_feature;
}

But I use the flowing code, in which I fix the one f to “age” exactly, it gets @@sgc_feature for “age” attribute is 8.5522, which is right.

CREATE DISTRIBUTED QUERY tg_sgc_v1(VERTEX<some_phone> seed, STRING feature, SET<STRING> features,
                                   STRING v_type, STRING e_type
                                  ) FOR GRAPH SomeGraph SYNTAX V1{ 
                                
                                                         
    MapAccum<STRING, FLOAT> @@sgc_feature;
                                    
    start = {seed};                      
    FOREACH f_ in features DO
        STRING f = f_;
        neighbor = SELECT t
               FROM start:s -(e_type:e)- v_type:t
               ACCUM
                   @@sgc_feature += (f -> t.getAttr("age", "FLOAT") / (sqrt(s.outdegree(e_type) + 1) * sqrt(t.outdegree(e_type) + 1)))               
               POST-ACCUM
                   @@sgc_feature += (f -> s.getAttr(f, "FLOAT") / (s.outdegree(e_type) + 1));                     
    END;                               
    PRINT @@sgc_feature;
}

Can any one figure out why?