[Resolved] Critical error after updating ACFML to 2.2.0 when saving existing options page

Hi Kor,
thanks for your reply.

Unfortunately, we’re not able to share WP admin credentials. However, I’m a bit confused about the situation:

According to the ticket you shared, the workaround/fix was already included in version 2.1.0. We are currently running ACFML 2.2.0, so the fix should already be part of this release, correct?

That’s why I’m not sure why we’re still hitting the same `md5(): Argument #1 ($string) must be of type string, array given` fatal error when saving our existing options page.

Could you please clarify:

* Was the fix from 2.1.0 fully merged into 2.2.0?
* Is there a known regression in 2.2.0 related to options pages?
* Are there any additional conditions (e.g. specific field types or configurations) that could still trigger this issue?

Thanks again for your support!
Best regards

Hi Kor,
thanks for your reply.

I’ve created a clean staging environment with a minimal setup where the issue is reproducible: hidden link

You can find the login credentials here: hidden link

The affected options page is called “Option Page for WPML”. On this staging site, you should be able to reproduce the issue by:

- Going to the options page
- Making any change
- Clicking “Save”

This immediately results in the same fatal error (md5(): Argument #1 ($string) must be of type string, array given).

The setup is intentionally minimal (only the necessary plugins and field configuration) to make debugging easier.

Please let me know if you need anything else.

Thanks a lot for taking a closer look

Best regards

Good morning,
Thank you for your feedback and for looking into this.

I can confirm that saving is now working properly on my end as well.

Does this mean that the behavior we experienced is a bug that will be fixed in an upcoming update? At the moment, we’re unable to roll out the new ACFML version across all of our production websites (around 270 sites) until this is officially resolved.

We’d appreciate a short confirmation on how this will be handled and whether a permanent fix is planned.

Thanks again for your support in the meantime.

Best regards,

Hi Kor,
Thanks for your suggestion. For us, this seems to be a bug.

Also, this issue did not occur in the previous version, so resaving would only be a temporary workaround, not a real solution.

In version 2.2.0, new functions were added for the option page, which we believe could be related to this bug. Please see the error log again—it clearly indicates a problem in ACFML.

While resaving the settings works on production sites, as mentioned, this is not an acceptable solution for our workflow, because resaving causes already defined translation settings for the fields to be lost, so it’s not an option for us.

For this reason, I ran some local tests and have narrowed down the problem:

I analyzed the field group, and the issue only occurs with the following fields:

```json
{
"key": "group_5f51e07d004b6",
"title": "Option Page",
"fields": [
{
"key": "field_62ece5f5daed8",
"label": "Group",
"name": "einstellungen_fixbuttons",
"aria-label": "",
"type": "group",
"instructions": "",
"required": 0,
"conditional_logic": 0,
"wrapper": {
"width": "",
"class": "",
"id": ""
},
"allow_in_bindings": 0,
"admin_only": 1,
"exclude_customer": 0,
"layout": "block",
"wpml_cf_preferences": 2,
"sub_fields": [
{
"key": "field_5f51e07d0072b",
"label": "Repeater",
"name": "fixbuttons",
"aria-label": "",
"type": "repeater",
"instructions": "",
"required": 0,
"conditional_logic": 0,
"wrapper": {
"width": "",
"class": "",
"id": ""
},
"allow_in_bindings": 0,
"wpml_cf_preferences": 2,
"admin_only": 1,
"exclude_customer": 0,
"collapsed": "",
"pagination": 1,
"min": 0,
"max": 0,
"layout": "table",
"button_label": "Fixbutton hinzufügen",
"rows_per_page": 20,
"sub_fields": [
{
"key": "field_5f51e07d239d8",
"label": "Link",
"name": "link",
"aria-label": "",
"type": "link",
"instructions": "",
"required": 0,
"conditional_logic": 0,
"wrapper": {
"width": "50",
"class": "",
"id": ""
},
"allow_in_bindings": 0,
"wpml_cf_preferences": 2,
"admin_only": 0,
"exclude_customer": 0,
"return_format": "array",
"parent_repeater": "field_5f51e07d0072b"
}
]
}
]
}
],
"location": [
[
{
"param": "options_page",
"operator": "==",
"value": "allgemein"
}
]
],
"menu_order": 0,
"position": "normal",
"style": "default",
"label_placement": "top",
"instruction_placement": "label",
"hide_on_screen": "",
"active": true,
"description": "",
"show_in_rest": 0,
"display_title": "",
"acfml_field_group_mode": "advanced",
"modified": 1772021065
}
```

Specifically, the field with the key 'field_5f51e07d239d8' has the translation setting value 2 ("wpml_cf_preferences": 2), which corresponds to “Translate”.

If I change this field’s value to 1 ("wpml_cf_preferences": 1), saving works perfectly. This strongly indicates that the issue is related to the "wpml_cf_preferences": 2 setting in this particular field group configuration.

We hope this information helps to reproduce and fix the issue in a future release.

Thanks again for your support!

Best regards,

Good morning,
thanks for escalating this.

I just checked the sandbox site and noticed that ACFML (Advanced Custom Fields Multilingual) is not installed there yet. Could you please install and activate ACFML on the sandbox as well?

As soon as it’s installed, I’ll go ahead and configure everything and replicate the problem for your 2nd Tier Support.

Thanks a lot for your help!

Best regards,

Would it be possible to use our staging environment instead? The issue is already reproducible there.

On your sandbox, I would first need to configure a large number of WPML settings to match our setup before I could even start reproducing the problem. Since our staging environment already mirrors the full configuration, it would be much more efficient to investigate the issue there.

You can access the staging site here:
hidden link

I’ve also enabled debug mode on our staging environment so that your 2nd level support / developers can directly review detailed logs if needed.

Please let me know if that works for you.

Thanks a lot!
Best regards,