Multiple Longtext causes problems (profile a.o.)

On develloping a new plugin (to create CV's) I've noticed a problem. When multiple 'longtext' textfields are used. Elgg DOES NOT want to save the content. But, when you disable the TinyMCE plugin that ships with Elgg, it DOES save all the textfields. You can easily replicate this problem when you add a new 'longtext' field to your PROFILE in start.php.

Is there any way to fix this?