That is very strange – not sure how WordPress would affect that, unless it is a JavaScript change.
In the header of the admin page containing your form, do you see the code that defines the max-submit limit? It should look something like this:
<script type=”text/javascript”>
/* Plugin: WP Max Submit Protect */
jQuery(document).ready(function($) {
$(‘form’).maxSubmit({
max_count: 2000,
max_exceeded_message: “This form has too many fields ({form_count}) for the server to accept (max {max_count})\nData may be lost if you submit. Are you sure you want to go ahead?”
});
})
</script>
If you can’t see that, then the form checker would fall back to the default 1000 fields.
I’ll take a look tonight to see what could be happening, and fix it ASAP. I suspect you are not seeing that code, because something has changed in the way JS is added to page headers.
In the meantime, either ignore the warning it gives when submitting (just hit “Okay”) or disable the plugin.
Thanks for reporting this.