ratiz Ta usando qual package?
Tive esse mesmo problema com alguns SVGs e o package flutter_svg. Eles tmé esse guia de como gerar os SVGs.
O mantenedor do package já afirmou que não vai adicionar a funcionalidade de interpretar a tag style pois, segundo ele, tornaria as coisas mais complexas. Então pra solucionar isso eu removo ela e aplico o valor do que tem na class diretamente onde é utilizada.
Ex:
SVG que dá erro na interpretação
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 50 50">
<defs>
<style>.cls-1{fill:#24c185;}.cls-2{fill:#f2f2f2;}</style>
</defs>
<g id="Camada_2" data-name="Camada 2"><g id="Camada_1-2" data-name="Camada 1"><circle class="cls-1" cx="25" cy="25" r="25"/><path class="cls-2" d="M31,35.5a.46.46,0,0,1-.23-.06l-6.27-3.29-6.26,3.29a.5.5,0,0,1-.73-.52l1.2-7L13.65,23a.53.53,0,0,1-.13-.52.51.51,0,0,1,.41-.34l7-1,3.14-6.35a.52.52,0,0,1,.89,0l3.14,6.35,7,1a.51.51,0,0,1,.41.34.52.52,0,0,1-.13.52l-5.07,4.94,1.2,7a.49.49,0,0,1-.5.58Zm-6.5-4.41a.52.52,0,0,1,.24.05l5.6,3-1.07-6.24a.51.51,0,0,1,.14-.44L34,23l-6.27-.91a.51.51,0,0,1-.37-.28l-2.81-5.67-2.8,5.67a.51.51,0,0,1-.37.28L15.07,23l4.53,4.42a.51.51,0,0,1,.15.44l-1.07,6.24,5.6-3A.46.46,0,0,1,24.51,31.09Z"/></g></g></svg>
SVG 'Corrigido'
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 50 50">
<g id="Camada_2" data-name="Camada 2">
<g id="Camada_1-2" data-name="Camada 1">
<circle fill="#24c185" cx="25" cy="25" r="25"/>
<path fill="#f2f2f2" d="M31,35.5a.46.46,0,0,1-.23-.06l-6.27-3.29-6.26,3.29a.5.5,0,0,1-.73-.52l1.2-7L13.65,23a.53.53,0,0,1-.13-.52.51.51,0,0,1,.41-.34l7-1,3.14-6.35a.52.52,0,0,1,.89,0l3.14,6.35,7,1a.51.51,0,0,1,.41.34.52.52,0,0,1-.13.52l-5.07,4.94,1.2,7a.49.49,0,0,1-.5.58Zm-6.5-4.41a.52.52,0,0,1,.24.05l5.6,3-1.07-6.24a.51.51,0,0,1,.14-.44L34,23l-6.27-.91a.51.51,0,0,1-.37-.28l-2.81-5.67-2.8,5.67a.51.51,0,0,1-.37.28L15.07,23l4.53,4.42a.51.51,0,0,1,.15.44l-1.07,6.24,5.6-3A.46.46,0,0,1,24.51,31.09Z"/>
</g>
</g>
</svg>