Semantic Predicate affected scope

Question

please consider the following grammar which gives me unexpected behavior:

lexer grammar TLexer;
WS                      : [ \t]+  -> channel(HIDDEN) ;
NEWLINE                 : '\n' -> channel(HIDDEN) ;
ASTERISK                : '*' ;
SIMPLE_IDENTIFIER       : [a-zA-Z_] [a-zA-Z0-9_$]* ;
NUMBER                  : [0-9] [0-9_]* ;

and

parser grammar TParser;
options { tokenVocab=TLexer; }
seq_input_list :
   level_input_list | edge_input_list ;

level_input_list :
  ( level_symbol_any )+ ;

edge_input_list :
  ( level_symbol_any )*  edge_symbol ;

level_symbol_any :
  {getCurrentToken().getText().matches("[0a]")}? ( NUMBER | SIMPLE_IDENTIFIER ) ;

edge_symbol :
  SIMPLE_IDENTIFIER | ASTERISK ;

The input 0 * is parsed fine but 0 f is not recognized by the parser (no viable alternative at input 'f'). If I change the ordering of rules in seq_input_list, both inputs are recognized.

My question to you is, if this indeed is an ANTLR issue or I understand the usage of semantic predicates wrong. I would expect the input 0 f to be recognized as (seq_input_list (edge_input_list (level_symbol_any ( NUMBER) edge_symbol ( SIMPLE_IDENTIFIER ) ) ).

Thank you in advance!

Julian