Preview doesn't work when adding a ticket as guest

[spirog]

when I tested whmcs v 8.1.3 using Twenty-one as parent and my own child theme php 7.4

Example:  reply Guest  asking for support...I  start to add a reply. when I click on Preview after adding anything it does not work, it shows the same coding as before i clicked on it.

no formatting whatsoever

here is an output of the error I see if its the correct error ?? 

 

Uncaught TypeError: Cannot read property 'body' of undefined
    at Object.onPreview (scripts.min.js?v=c8b4ae:8)
    at t.showPreview (scripts.min.js?v=c8b4ae:9)
    at callback (scripts.min.js?v=c8b4ae:9)
    at t.__handle (scripts.min.js?v=c8b4ae:9)
    at HTMLButtonElement.i (scripts.min.js?v=c8b4ae:1)
    at HTMLDivElement.dispatch (scripts.min.js?v=c8b4ae:3)
    at HTMLDivElement.m.handle (scripts.min.js?v=c8b4ae:2)
onPreview @ scripts.min.js?v=c8b4ae:8
showPreview @ scripts.min.js?v=c8b4ae:9
callback @ scripts.min.js?v=c8b4ae:9
__handle @ scripts.min.js?v=c8b4ae:9
i @ scripts.min.js?v=c8b4ae:1
dispatch @ scripts.min.js?v=c8b4ae:3
m.handle @ scripts.min.js?v=c8b4ae:2
scripts.min.js?v=c8b4ae:2 [Violation] 'click' handler took 676ms

anyone have an Idea how to correct this ?