Members of the (state, liberal) Lutheran Church in Poland by their public confession (church membership) do not share our doctrinal stance on various issues, so sharing in communion would normally be out of order.

But it is conceivable that a person's private confession may differ from his public confession and be in agreement with ours, so expressions of fellowship may be allowed for a time under special circumstances. An evangelical, pastoral decision on this would require additional information about the situation, why the person apparently holds formal membership in a given church, what that membership really means or doesn't mean in that situation, and what factors are involved. Pastoral practice will also be aware of interested observers who may not know the situation. Sometimes expressions of genuine fellowship are fitting, but spiritual offense might be given or the appearance of disorderliness might result. So it could be permissible in principle but unwise in practice.

More might be said, but this will hopefully serve to show that seeking a definite or absolute Yes or No to such a question would not be too helpful.