Seq is already in use/consumed by another Seq

gistfile1.txt

⚠ mbf Use of Nil in string context
⚠ mbf   in sub escape-text at /Users/alex/.rakubrew/versions/moar-/share/perl6/site/sources/680B4AEEA3A4AB438E2736C0F26B747283AD960D (Cro::WebApp::Template::AST) line 320
⚠ mbf The iterator of this Seq is already in use/consumed by another Seq (you
⚠ mbf might solve this by adding .cache on usages of the Seq, or by assigning
⚠ mbf the Seq into an array)
⚠ mbf   in sub  at EVAL_107 line 67
⚠ mbf   in method render at /Users/alex/.rakubrew/versions/moar-/share/perl6/site/sources/1506380118C6D13DBE13C8BBA12FF9DEF61180C3 (Cro::WebApp::Template::Repository) line 26
⚠ mbf   in sub render-internal at /Users/alex/.rakubrew/versions/moar-/share/perl6/site/sources/A908E2E7C6DCB4C8363F96664B5F5C06FEC40A66 (Cro::WebApp::Template) line 67
⚠ mbf   in sub render-template at /Users/alex/.rakubrew/versions/moar-/share/perl6/site/sources/A908E2E7C6DCB4C8363F96664B5F5C06FEC40A66 (Cro::WebApp::Template) line 60
⚠ mbf   in sub template at /Users/alex/.rakubrew/versions/moar-/share/perl6/site/sources/A908E2E7C6DCB4C8363F96664B5F5C06FEC40A66 (Cro::WebApp::Template) line 187
⚠ mbf   in block  at app.raku line 265
⚠ mbf   in block  at /Users/alex/.rakubrew/versions/moar-/share/perl6/site/sources/8254A39B6949B97BBDC7CBA37FD45100EC77F9CB (Cro::HTTP::Router) line 189
⚠ mbf   in block  at /Users/alex/.rakubrew/versions/moar-/share/perl6/site/sources/8254A39B6949B97BBDC7CBA37FD45100EC77F9CB (Cro::HTTP::Router) line 185