If you want your upcoming events list to be “static” ie: the same in all circumstances and NOT to respond to query parameters such as category id, then add a parameter “ignore_query=1” to the widgets or shortcodes parameters.
This tells the plugin to NOT respond to any parameters passed via the query string. Please use this only after due consideration and understanding and probably only in the “upcoming events list”.
This will force the list to be “static” and appear the same no matter whether in a category/tag/author archive or not. If you are using the box calendar or taxonomy widget to link through to a agenda/calendar page, do NOT use this in the calendar page shortcode.