[perl #66250] Trouble with white space in Rakudo grammars

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# New Ticket Created by  Håkon Skaarud Karlsen 
# Please include the string:  [perl #66250]
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This works:
  grammar A { rule TOP { 'a ' 'b' {*} } }; my $m = A.parse('a b'); say $/;
Result: "a b"
Expected result: "a b"

This doesn't work:
  grammar A { rule TOP { 'a' ' b' {*} } }; my $m = A.parse('a b'); say $/;
Result: Empty string
Expected result: "a b"

And this doesn't work:
  grammar A { rule TOP { 'a' <blank> 'b' {*} } }; my $m = A.parse('a
b'); say $/;
Result: Empty string
Expected result: "a b"

Håkon S Karlsen