Duplicate content in body

[Creanics]

Describe the bug
When i use $mail->getTextBody(), i have 4 times the content :
if in my mail i have just hello There\n i the function will return hello There\nhello There\nhello There\nhello There\n

To Reproduce
Steps to reproduce the behavior:

1. Fetch your mails
2. Create a variable with getTextBody like $body = $mail->getTextBody()
3. Dump your variable
4. See that your content is duplicated

Expected behavior
Content not duplicated when using the function

Screenshots
There is my mail (when i go to the webmail) :

And this is the dump of $mail->getTextBody() :

Desktop / Server (please complete the following information):

• OS: Windows11
• PHP: 8.1.10
• Version 6.1.0

Additional context
When I was using v4.12 I didn't have this problem