Both volumes of Spy Classroom are throwing a weird error for me in calibre, but only on the cover page. Don't know if anyone else is getting something similar. calibre, version 7.17.0 ERROR: Unhandled error: Unknown error Traceback (most recent call last): at IframeBoss.update_toc_position (userscript:viewer.js:29477:31) at update_visible_toc_anchors (userscript:viewer.js:28305:19) at current_toc_anchor_map (userscript:viewer.js:28290:31) at recalculate_toc_anchor_positions (userscript:viewer.js:28261:57) at position_for_anchor (userscript:viewer.js:20300:17) at ensure_page_list_target_is_displayed (userscript:viewer.js:20279:24) TypeError: Failed to execute 'getComputedStyle' on 'Window': parameter 1 is not of type 'Element'.

it is because they are reuploading epubs that have been modified and injected with an ad page by the site they got this from.