What version of bootstrap are you using - 4 or 5?
How are you creating the accordion? I just tested using the Accordion Cards component in Wappler and see no such error.
What page are you working on - a regular page, a content page? What site is this - SPA or a regular page? What server model?
Please make sure to post your topics in the proper category, all of your recent posts are posted without any category selected - this makes it hard to follow.
Also, make sure to not just randomly post code in the posts, but format it: