I don't know if this plugin is still being maintained, but if it is I think the implementation of the search is not entirely correct.
According to the Joplin search syntax an expression such as any:1 tag:foo tag:bar should be permitted and deliver objects containing either the tag foo or the tag bar, whereas any:0 tag:foo tag:bar should return objects containing both foo and bar.
In case of any:1 this is not what is happening in the agenda panel; instead, using any:1 returns every todo, regardless of the tag.