Plugin produces JS errors inside Block editor

WP 6.1.1, TT3 theme, no other plugins active:

Post does not have any SVG in it, just a new blog entry screen with a paragraph block.

react-dom.js?ver=17.0.1:61 Warning: WithState(WithSelect(WithDispatch(CheckBoxCustom))).state: must be set to an object or null
    at WrappedComponent (http://nextgenthemes.test/wp/wp-includes/js/dist/compose.js?ver=70668e5bb5fde21b1e2c:2989:9)
    at FilteredComponentRenderer (http://nextgenthemes.test/wp/wp-includes/js/dist/components.js?ver=2415973c4227a31b8a15:64129:9)
    at http://nextgenthemes.test/wp/wp-includes/js/dist/data.js?ver=03a7e3ef4d75081d1a5e:4218:25
    at http://nextgenthemes.test/wp/wp-includes/js/dist/data.js?ver=03a7e3ef4d75081d1a5e:4060:22
    at <anonymous> (http://nextgenthemes.test/wp/wp-includes/js/dist/compose.js?ver=70668e5bb5fde21b1e2c:2604:10)
    at Component (http://nextgenthemes.test/wp/wp-includes/js/dist/components.js?ver=2415973c4227a31b8a15:64292:89)
    at div
    at PanelBody (http://nextgenthemes.test/wp/wp-includes/js/dist/components.js?ver=2415973c4227a31b8a15:58727:5)
    at PostTypeSupportCheck (http://nextgenthemes.test/wp/wp-includes/js/dist/editor.js?ver=04f9e2ef78d16f9a9f44:6536:5)
    at http://nextgenthemes.test/wp/wp-includes/js/dist/data.js?ver=03a7e3ef4d75081d1a5e:4060:22
    at <anonymous> (http://nextgenthemes.test/wp/wp-includes/js/dist/compose.js?ver=70668e5bb5fde21b1e2c:2604:10)
    at ThemeSupportCheck (http://nextgenthemes.test/wp/wp-includes/js/dist/editor.js?ver=04f9e2ef78d16f9a9f44:7338:5)
    at http://nextgenthemes.test/wp/wp-includes/js/dist/data.js?ver=03a7e3ef4d75081d1a5e:4060:22
    at <anonymous> (http://nextgenthemes.test/wp/wp-includes/js/dist/compose.js?ver=70668e5bb5fde21b1e2c:2604:10)
    at PostFeaturedImageCheck
    at FeaturedImage (http://nextgenthemes.test/wp/wp-includes/js/dist/edit-post.js?ver=78b9ccdebe3cb8c66859:7528:5)
    at http://nextgenthemes.test/wp/wp-includes/js/dist/data.js?ver=03a7e3ef4d75081d1a5e:4218:25
    at http://nextgenthemes.test/wp/wp-includes/js/dist/data.js?ver=03a7e3ef4d75081d1a5e:4060:22
    at <anonymous> (http://nextgenthemes.test/wp/wp-includes/js/dist/compose.js?ver=70668e5bb5fde21b1e2c:2604:10)
    at div
    at Panel (http://nextgenthemes.test/wp/wp-includes/js/dist/components.js?ver=2415973c4227a31b8a15:58670:5)
    at div
    at SlotComponent (http://nextgenthemes.test/wp/wp-includes/js/dist/components.js?ver=2415973c4227a31b8a15:18370:5)
    at Slot
    at http://nextgenthemes.test/wp/wp-includes/js/dist/components.js?ver=2415973c4227a31b8a15:18961:5
    at ComplementaryAreaSlot (http://nextgenthemes.test/wp/wp-includes/js/dist/edit-post.js?ver=78b9ccdebe3cb8c66859:1448:5)
    at div
    at div
    at div
    at div
    at InterfaceSkeleton (http://nextgenthemes.test/wp/wp-includes/js/dist/edit-post.js?ver=78b9ccdebe3cb8c66859:1679:5)
    at Layout (http://nextgenthemes.test/wp/wp-includes/js/dist/edit-post.js?ver=78b9ccdebe3cb8c66859:8946:5)
    at ErrorBoundary (http://nextgenthemes.test/wp/wp-includes/js/dist/editor.js?ver=04f9e2ef78d16f9a9f44:6209:5)
    at BlockRefsProvider (http://nextgenthemes.test/wp/wp-includes/js/dist/block-editor.js?ver=9163831602133591bad9:10459:5)
    at BlockEditorProvider (http://nextgenthemes.test/wp/wp-includes/js/dist/block-editor.js?ver=9163831602133591bad9:21452:5)
    at http://nextgenthemes.test/wp/wp-includes/js/dist/block-editor.js?ver=9163831602133591bad9:21153:7
    at WithRegistryProvider(BlockEditorProvider)
    at BlockContextProvider (http://nextgenthemes.test/wp/wp-includes/js/dist/block-editor.js?ver=9163831602133591bad9:14802:5)
    at EntityProvider (http://nextgenthemes.test/wp/wp-includes/js/dist/core-data.js?ver=7f0e550a9fa7a0fe5852:6045:5)
    at EntityProvider (http://nextgenthemes.test/wp/wp-includes/js/dist/core-data.js?ver=7f0e550a9fa7a0fe5852:6045:5)
    at EditorProvider (http://nextgenthemes.test/wp/wp-includes/js/dist/editor.js?ver=04f9e2ef78d16f9a9f44:12438:5)
    at http://nextgenthemes.test/wp/wp-includes/js/dist/editor.js?ver=04f9e2ef78d16f9a9f44:12198:5
    at WithRegistryProvider(EditorProvider)
    at SlotFillProvider (http://nextgenthemes.test/wp/wp-includes/js/dist/components.js?ver=2415973c4227a31b8a15:18801:5)
    at provider_SlotFillProvider (http://nextgenthemes.test/wp/wp-includes/js/dist/components.js?ver=2415973c4227a31b8a15:18824:5)
    at Provider (http://nextgenthemes.test/wp/wp-includes/js/dist/components.js?ver=2415973c4227a31b8a15:18975:5)
    at div
    at ShortcutProvider (http://nextgenthemes.test/wp/wp-includes/js/dist/keyboard-shortcuts.js?ver=d9997e5c243ce7427d4e:778:75)
    at Editor (http://nextgenthemes.test/wp/wp-includes/js/dist/edit-post.js?ver=78b9ccdebe3cb8c66859:9226:5)