Why is part of the $_POST array truncated when submitting the form?

Question

PHP

Hello colleagues!
There is a form with a large number of fields (50+) and two submit buttons:

<form name="form" enctype="multipart/form-data" method="post" action="...">
   <button type="submit" name="submit">Сохранить</button>
   <button type="submit" name="submit_enabled">Включить</button> 
   ...поля...
</form>

On the backend, the code that handles pressing both buttons is the same (!).
The essence of the problem: When you press the "Save" button, all the data comes to the backend (the entire $_POST array), and when you press the "Enable" button, sometimes (!) the full data comes (part of the $_POST array is cut off at the end). Moreover, it is not always cut off on the same character - but "floats".
The following settings are on the server (PHP 5.6):
max_input_vars = 5000
post_max_size = 256M
memory_limit = 2048M
It seems to me that it's not in my code. What then? Server settings? Bug in php?
Can anyone come across?
Thank you.

Answer 1

I don’t know what the problem is, but I know how I would look - I would try my best to achieve repeatability.

sometimes (!) come to full data

- so you won't find anything.
Catch the clipped data and resend with the same data - again it was clipped, but not with the others? Look for the difference in the data.

Answer 2

You need to check what is sent to the server in the developer console in the browser. Perhaps the problem is in the layout of the form with a large number of fields.

Answer 3

Look for the bug in one of the fields or one of the values.

Answer 4

Try to send a save request via rest http tools, if the result is the same problem on the backend, if not, then on the layout