What is the problem in simpla editor?

Question

TinyMCE

Hello, I had a problem editing pages, photos and videos stopped loading, an error is generated in this type of console

Uncaught TypeError: Cannot read property 'getContent' of null
    at generate_meta_description (index.php?module=PageAdmin&id=2&return=%2Fsimpla%2Findex.php%3Fmodule%3DPagesAdmin:124)
    at HTMLDocument.<anonymous> (index.php?module=PageAdmin&id=2&return=%2Fsimpla%2Findex.php%3Fmodule%3DPagesAdmin:70)
    at n (VM2207 jquery.js:2)
    at Object.fireWith (VM2207 jquery.js:2)
    at Function.ready (VM2207 jquery.js:2)
    at HTMLDocument.B (VM2207 jquery.js:2)
generate_meta_description @ index.php?module=PageAdmin&id=2&return=%2Fsimpla%2Findex.php%3Fmodule%3DPagesAdmin:124
(anonymous) @ index.php?module=PageAdmin&id=2&return=%2Fsimpla%2Findex.php%3Fmodule%3DPagesAdmin:70
n @ jquery.js:2
fireWith @ jquery.js:2
ready @ jquery.js:2
B @ jquery.js:2
qW6N3AyJHhk.jpg:1 GET https://site.ru/images/test/qW6N3AyJHhk.jpg 404 (Not Found)

when trying to load something
at generate_meta_description (index.php?module=PageAdmin&id=2&return=%2Fsimpla%2Findex.php%3Fmodule%3DPagesAdmin:124) it
refers to an error

description = tinyMCE.get("body").getContent().replace(/(<([^>]+)>)/ig," ").replace(/(\&nbsp;)/ig," ").replace(/^\s+|\s+$/g, '').substr(0, 512);

and at HTMLDocument. (index.php?module=PageAdmin&id=2&return=%2Fsimpla%2Findex.php%3Fmodule%3DPagesAdmin:70) refers to

if($('textarea[name="meta_description"]').val() == generate_meta_description() || $('textarea[name="meta_description"]').val() == '')

costs tinymce 5 version