Wikitext.parseTemplates() doesn't properly handle usage of | in values

[Retrocast]

This wikitext is correctly parsed on wiki (image1 is a proper gallery element):

{{Card
|title1=Squirrel
|image1=
<gallery>
Squirrel.png | Act I
Gbc squirrel.png | Act II
</gallery>
|cost=Free
|health=1
|power=0
|tribe=[[:Category:Squirrel|Squirrel]]
}}

But parseTemplates incorrectly parses it as bunch of positional parameters instead:

Template {
  wikitext: '...',
  parameters: [
    Parameter {
      name: 'title1',
      value: 'Squirrel',
      wikitext: '|title1=Squirrel\n'
    },
    Parameter {
      name: 'image1',
      value: '<gallery>\nSquirrel.png',
      wikitext: '|image1=\n<gallery>\nSquirrel.png '
    },
    Parameter {
      name: 1,
      value: 'Act I\nGbc squirrel.png',
      wikitext: '| Act I\nGbc squirrel.png '
    },
    Parameter {
      name: 2,
      value: 'Act II\n</gallery>',
      wikitext: '| Act II\n</gallery>\n'
    },
    Parameter { name: 'cost', value: 'Free', wikitext: '|cost=Free\n' },
    Parameter { name: 'health', value: '1', wikitext: '|health=1\n' },
    Parameter { name: 'power', value: '0', wikitext: '|power=0\n' },
    Parameter {
      name: 'tribe',
      value: '[[:Category:Squirrel|Squirrel]]',
      wikitext: '|tribe=[[:Category:Squirrel|Squirrel]]\n'
    }
  ],
  name: 'Card'
}