Null deprecation in mail

[kiatng]

I have this error in the log:

    [type] => 8192:E_DEPRECATED
    [message] => strtr(): Passing null to parameter #1 ($string) of type string is deprecated
    [file] => .../vendor/shardj/zf1-future/library/Zend/Mail.php
    [line] => 1223

Probably from

magento-lts/app/code/core/Mage/Sales/Model/Order/Invoice.php

Line 780 in a42a85b

public function sendEmail($notifyCustomer = true, $comment = '')

Preconditions (*)

1. PHP8

Steps to reproduce (*)

1. Not sure how

Expected result (*)

1. [Screenshots, logs or description]

Actual result (*)

1. [Screenshots, logs or description]

[fballiano]

did it happen again? do you have more info like a backtrace?