Hi @RetroProgrammist. Thank you for your report.
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Hi @engcom-Bravo. Thank you for working on this issue.
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@magento give me 2.4-develop instance

Hi @engcom-Bravo. Thank you for your request. I'm working on Magento instance for you.

Hi @engcom-Bravo, here is your Magento Instance: https://d4233eab37c46bc3ab6df90e65481f53.instances-prod.magento-community.engineering
Admin access: https://d4233eab37c46bc3ab6df90e65481f53.instances-prod.magento-community.engineering/admin_375a
Login: b45884d9
Password: 397c2e4f4f9b

Hi @RetroProgrammist,

Thanks for your reporting and collaboration.

We have verified the issue in Latest 2.4-develop instance and the issue is reproducible.Kindly refer the attached screenshot.

Steps to reproduce

• create Simple product (i used sampledata)

• Create custom option:

  -Checkbox type
  -Require
  -1 or 2 option values

• Go to front, log in

• Add the product to cart !!WARNING choose only 1 option value, eg. Checkbox 1 on screen above

• Create an Order

• Then go to Accaunt and reorder this order

We're getting an error Some of the selected item options are not currently available.

Hence Confirming the issue.

Thanks.

✅ Jira issue https://jira.corp.adobe.com/browse/AC-11970 is successfully created for this GitHub issue.

✅ Confirmed by @engcom-Bravo. Thank you for verifying the issue.
Issue Available: @engcom-Bravo, You will be automatically unassigned. Contributors/Maintainers can claim this issue to continue. To reclaim and continue work, reassign the ticket to yourself.

Facing the same issue in Magento2.4.5p2 Cloud

These 2 lines of code fixes the issue. Tested in 2.4.5-p8.

diff --git a/vendor/magento/module-catalog/Model/Product/Option/Select.php b/vendor/magento/module-catalog/Model/Product/Option//Select.php
index 286fa39..b0db2f3 100644
--- a/Select.php
+++ b/Select.php
@@ -99,6 +99,8 @@ class Select extends \Magento\Catalog\Model\Product\Option\Type\DefaultType
         if (!$this->_isSingleSelection()) {
             if (is_string($value)) {
                 $value = explode(',', $value);
+            } else {
+                $value = [$value];
             }
             $valuesCollection = $option->getOptionValuesByOptionId($value, $this->getProduct()->getStoreId())->load();
             $valueCount = is_array($value) ? count($value) : 0;

This can be fixed this Creating the Custom Patch . Tested in Magento 2.4.5p2 Cloud

diff --git a/vendor/magento/module-catalog/Model/Product/Option/Type/Select.php b/vendor/magento/module-catalog/Model/Product/Option/Type/Select.php
index 3ee2rd..8349152 111644
--- a/vendor/magento/module-catalog/Model/Product/Option/Type/Select.php
+++ b/vendor/magento/module-catalog/Model/Product/Option/Type/Select.php
@@ -101,7 +101,7 @@
                 $value = explode(',', $value);
             }
             $valuesCollection = $option->getOptionValuesByOptionId($value, $this->getProduct()->getStoreId())->load();
-            $valueCount = is_array($value) ? count($value) : 0;
+            $valueCount = is_array($value) ? count($value) : 1;
             if ($valuesCollection->count() != $valueCount) {
                 $this->setIsValid(false);
                 throw new LocalizedException( 

@magento I am working on this