TypeError: strlen(): Argument #1 ($string) must be of type string, array given in strlen()

At times when the above error is not thrown (i don't know why/when) then an other error appears:
TypeError: strlen(): Argument #1 ($string) must be of type string, array given in strlen(). I've added the error stack of this too in attachment (error-stack-2).

Any help would be very appreciated!

If the community has to do all the troubleshooting you may not get an answer. Please could you upload the minimal form that reproduces the bug?

I expect there are warnings logged in PHP 7.4.

Thanks for your answer @cilifen!
The Yaml file i uploaded is the form which causes the problem. If you fill it out until the end, you get the error.
Or do you mean something else?

There are thirty-six form elements in the form. Which one is the cause? As this is a bug report I think it is your responsibility to provide the smallest possible form that reproduces the bug. We frequently ask this of community members who post bugs.

Thanks cilefen! I created a small sample form which reproduces the error!
I think it's caused by the "preview" of the form. Because when i disable the preview, it works perfectly!
So in Sample page 1 choose "option 2", in sample page 2 also option 2 and press "preview" in sample page 3.
Form attached!

Please review.

Sorry i'm new to this... What should i review? Or how can i test your solution?

@cilefen should i create a new issue for the "strlen" error? Because the fix for the "strpos" error is already created in this issue i think:
https://www.drupal.org/project/webform/issues/3345964 🐛 Conditionally hidden text format field results in errors and wsod Fixed

Or, edit this one to be just the remaining matter.

That issue is about the strpos() error. The one that i have left now is the strlen() error...

Close this as a duplicate or edit to be about the strlen issue. Right now, there are two issues reported in this issue.

@cilefen: i've edited the issue to be about the issue with strlen. Thanks for the advice! Hopefully there is a fix soon!

@see 🐛 Conditionally hidden text format field results in errors and wsod Fixed

Automatically closed - issue fixed for 2 weeks with no activity.