js error in admin for some posts

Getting this javascript error in admin for some posts in Yoast metabox – content optimization fields do not display:

wp-seo-metabox-category-840.min.js?ver=8.4:1 Uncaught TypeError: y is not a function
    at i (wp-seo-metabox-category-840.min.js?ver=8.4:1)
    at HTMLInputElement.<anonymous> (wp-seo-metabox-category-840.min.js?ver=8.4:1)
    at Function.each (load-scripts.php?c=0&load[]=jquery-core,jquery-migrate,utils,jquery-ui-core,jquery-ui-widget,jquery-ui-mouse,jquery-ui-sortable,underscore,wp-util,moxiejs,p&load[]=lupload&ver=4.9.8:2)
    at a.fn.init.each (load-scripts.php?c=0&load[]=jquery-core,jquery-migrate,utils,jquery-ui-core,jquery-ui-widget,jquery-ui-mouse,jquery-ui-sortable,underscore,wp-util,moxiejs,p&load[]=lupload&ver=4.9.8:2)
    at c (wp-seo-metabox-category-840.min.js?ver=8.4:1)
    at Object.<anonymous> (wp-seo-metabox-category-840.min.js?ver=8.4:1)
    at Function.each (load-scripts.php?c=0&load[]=jquery-core,jquery-migrate,utils,jquery-ui-core,jquery-ui-widget,jquery-ui-mouse,jquery-ui-sortable,underscore,wp-util,moxiejs,p&load[]=lupload&ver=4.9.8:2)
    at a.fn.init.each (load-scripts.php?c=0&load[]=jquery-core,jquery-migrate,utils,jquery-ui-core,jquery-ui-widget,jquery-ui-mouse,jquery-ui-sortable,underscore,wp-util,moxiejs,p&load[]=lupload&ver=4.9.8:2)
    at a.fn.init.e.fn.initYstSEOPrimaryCategory (wp-seo-metabox-category-840.min.js?ver=8.4:1)
    at HTMLDocument.<anonymous> (epc-taxonomy-metabox.js:226)

Some work fine, some don’t. Yoast SEO Premium 8.4, WP 4.9.8, custom theme with ACF pro, hosted on pantheon.io, nginx, redis