ich sehe das hier am ende vom 'quick css' abschnitt, der im header embedded ausgegeben wird:
.page-id-4109 .image_overlay_effect, .image_overlay_effect_inside { top: 45px;}#top .cart_dropdown .dropdown_widget li a{color:#181919;}.woocommerce_tabs .tabs a, .product_meta, .quantity input.qty, .cart_dropdown .dropdown_widget, #top .sub_menu li ul a, .avia_select_fake_val, address, .product>a .product_excerpt, .term_description{color:#898888;}.quantity input, .cart_dropdown .dropdown_widget li, .cart_dropdown .dropdown_widget div, .cart_dropdown .dropdown_widget img, #top .sub_menu ul ul li, .thumbnails_container li, .thumbnails_container li span, #top .comment-text, div #reviews li .avatar, div .widget_price_filter .ui-slider-horizontal .ui-slider-range, .entry-content .avia_select_unify, .addresses.col2-set .col-1, .addresses.col2-set .col-2, .payment_methods, .payment_methods li, #payment, .avia_cart, form.login, #top div .chzn-container-single .chzn-single, #top div .chzn-container-single .chzn-single div {border-color:#e1e1e1;}#top div.product .woocommerce_tabs ul.tabs li.active a, .quantity input.qty, .cart_dropdown .dropdown_widget, #top .sub_menu li ul a, #payment{background-color:#f0efef;}.woocommerce_tabs ul.tabs, .activeslideThumb, #payment li{background-color:#e6e6e6;}.summary div{border-color:#e6e6e6;}#top .sub_menu li li a:hover, div .widget_price_filter .ui-slider-horizontal .ui-slider-range, div .widget_price_filter .price_slider_wrapper .ui-widget-content, .avia_cart{background-color:#e6e6e6;}div .quantity input.plus, div .quantity input.minus, #shop_header a:hover, #top .widget_layered_nav ul li.chosen a, #top .widget_layered_nav ul li.chosen small{color:#f0efef;}div .quantity input.plus, div .quantity input.minus, div .widget_layered_nav ul li.chosen, div .widget_price_filter .price_slider_wrapper .price_slider .ui-slider-handle, #top a.remove{background-color:#212121;}#top .bbp-forum-title, #top .bbp-topic-title a{color:#212121;}#top .template-forum-wrap div, .bbp-pagination-links, .bbp-pagination-links span, .bbp-pagination-links a, #top .bbp-topic-pagination a, #bbp-your-profile span, img.avatar, table ul{border-color:#e1e1e1;}#top .bbp-pagination, #top .bbp-topic-pagination a, #entry-author-info #author-description, div.bbp-breadcrumb a, .bbp_widget_login .bbp-lostpass-link:after{color:#898888;}.bbp-admin-links{color:#e1e1e1;}
das hier
.page-id-4109 .image_overlay_effect, .image_overlay_effect_inside { top: 45px;}
ist der zweitletzte style in deinem geposteten styles; du kannst sehen, dass der #header style nicht da ist, dafuer eine menge anderer styles.
entweder ist das ein caching-problem oder ein theme-problem, in welchem fall es das beste waere den theme autor anzuschreiben.