Separator Block loaded twice

Hey guys, apologies if this is obvious; I’ve still got my block theme training wheels on. When inserting a default or Wide Line Separator block into a page, it’s being loaded twice. Styled by WP Core and again by core-separator.css Dots and Dotted styles are no problem.
What am I missing?
Screenshot Link

Also, Thin is disabled in core-separator.css

.is-style-separator-thin {
	border: none !important;
}

Why would the Thin option still be displayed in the block styles selector UI if it’s not available?

.editor-styles-wrapper .wp-block-separator {
    color: var(--wp--preset--color--main);
    font-size: var(--wp--preset--font-size--large);
}

<style>
.editor-styles-wrapper .is-layout-constrained > :where(:not(.alignleft):not(.alignright):not(.alignfull)) {
    max-width: var(--wp--style--global--content-size);
    margin-left: auto !important;
    margin-right: auto !important;
}
.wp-block-separator:not(.is-style-dots), .wp-block-separator.has-background:not(.is-style-dots) {
    border-bottom: 1px solid currentColor;
    height: 1px;
}
.block-editor-block-list__block[data-type="core/separator"] {
    padding-bottom: .1px;
    padding-top: .1px;
}
.block-editor-block-list__layout .block-editor-block-list__block {
    overflow-wrap: break-word;
    pointer-events: auto;
    position: relative;
    -webkit-user-select: text;
    user-select: text;
}
<style>
.editor-styles-wrapper *, .editor-styles-wrapper *::before, .editor-styles-wrapper *::after {
    box-sizing: inherit;
}
<style>
.editor-styles-wrapper :where(body .is-layout-constrained) > * {
    margin-block-start: var(--wp--preset--spacing--medium);
    margin-block-end: 0;
}
.wp-block-separator {
    opacity: 1;
}
.wp-block-separator {
    border: none;
    border-top: 2px solid;