Catalog Promotion Smarty bug

CS-Cart 4.20.1 PHP 8.1
When you add a new Catalog Promotion (?dispatch=promotions.add&zone=catalog), the Bug Tracker throws this:

PHP Deprecated

Message

explode(): Passing null to parameter #2 ($string) of type string is deprecated

Error at

app/lib/vendor/smarty/smarty/src/Extension/CallbackWrapper.php, line: 29

Backtrace

File: app/lib/vendor/smarty/smarty/src/Extension/CallbackWrapper.php
Line: 29
Function: {closure}
File: var/cache/templates/backend/273a5f6fc057627dcd95ba83dbf2e39affd479f0_2.tygh_general_content.post.tpl.php
Line: 29
Function: handle
File: app/lib/vendor/smarty/smarty/src/Template/GeneratedPhpFile.php
Line: 111
Function: content_69c7d4dad7c058_62796543
File: app/lib/vendor/smarty/smarty/src/Template/Compiled.php
Line: 110
Function: getRenderedTemplateCode
File: app/lib/vendor/smarty/smarty/src/Template.php
Line: 180
Function: render
File: app/lib/vendor/smarty/smarty/src/Template.php
Line: 655
Function: render
File: app/lib/vendor/smarty/smarty/src/Template.php
Line: 589
Function: _execute
File: app/Tygh/SmartyEngine/Core.php
Line: 85
Function: fetch
File: app/Tygh/SmartyEngine/Blocks/Hook.php
Line: 140
Function: fetch
File: var/cache/templates/backend/d89eacdd182a0b24cc2e723c1af5d75eb0f088da_2.tygh_update.tpl.php
Line: 431
Function: handle
File: app/lib/vendor/smarty/smarty/src/Template/GeneratedPhpFile.php
Line: 111
Function: content_69c7d4dac93833_74453051
File: app/lib/vendor/smarty/smarty/src/Template/Compiled.php
Line: 110
Function: getRenderedTemplateCode
File: app/lib/vendor/smarty/smarty/src/Template.php
Line: 180
Function: render
File: app/lib/vendor/smarty/smarty/src/Template.php
Line: 287
Function: render
File: var/cache/templates/backend/d49b3ada91aa41c5ad19b080d33606ae24dc64b2_2.tygh_index.tpl.php
Line: 175
Function: renderSubTemplate
File: app/lib/vendor/smarty/smarty/src/Template/GeneratedPhpFile.php
Line: 111
Function: content_69b3e7b4ca8cb9_13968983
File: app/lib/vendor/smarty/smarty/src/Template/Compiled.php
Line: 110
Function: getRenderedTemplateCode
File: app/lib/vendor/smarty/smarty/src/Template.php
Line: 180
Function: render
File: app/lib/vendor/smarty/smarty/src/Template.php
Line: 655
Function: render
File: app/lib/vendor/smarty/smarty/src/Template.php
Line: 589
Function: _execute
File: app/Tygh/SmartyEngine/Core.php
Line: 85
Function: fetch
File: app/functions/fn.control.php
Line: 639
Function: fetch
File: admin.php
Line: 27
Function: fn_dispatch

I’m afraid, but I was unable to reproduce this issue.