Error on Channel Form in EE7.4

[DalizPR]

Getting an error in a {exp:channel:form} which submits to a channel with 2 or more category groups … in the new EE 7.4. The form was working fine in EE 7.3.x. If I remove a category group (so there is only 1 category group, it works).

The error is:

Warning
Undefined array key "categories[cat_group_id_2]"
ee/ExpressionEngine/Model/Content/Display/DefaultLayout.php, line 72

Severity: E_WARNING
Error Caught
Call to a member function getId() on null
ee/ExpressionEngine/Model/Content/Display/LayoutTab.php:49

Stack Trace: Please include when reporting this error
#0 ee/ExpressionEngine/Model/Content/Display/DefaultLayout.php(72): ExpressionEngine\Model\Content\Display\LayoutTab->addField(NULL)
#1 ee/ExpressionEngine/Model/Channel/Display/DefaultChannelLayout.php(225): ExpressionEngine\Model\Content\Display\DefaultLayout->transform(Array)
#2 ee/ExpressionEngine/Model/Channel/ChannelEntry.php(863): ExpressionEngine\Model\Channel\Display\DefaultChannelLayout->transform(Array)
#3 ee/ExpressionEngine/Addons/channel/libraries/channel_form/Channel_form_lib.php(998): ExpressionEngine\Model\Channel\ChannelEntry->getDisplay()
#4 ee/ExpressionEngine/Addons/channel/libraries/channel_form/Channel_form_lib.php(270): Channel_form_lib->_build_custom_field_variables()
#5 ee/ExpressionEngine/Addons/channel/mod.channel.php(5139): Channel_form_lib->entry_form()
#6 ee/legacy/libraries/Template.php(1831): Channel->form()
#7 ee/legacy/libraries/Template.php(1506): EE_Template->process_tags()
#8 ee/legacy/libraries/Template.php(625): EE_Template->tags()
#9 ee/legacy/libraries/Template.php(248): EE_Template->parse('{!-- ra:0000000...', false, 1, false)
#10 ee/legacy/libraries/Template.php(178): EE_Template->fetch_and_parse('', '', false)
#11 ee/legacy/libraries/Core.php(811): EE_Template->run_template_engine('', '')
#12 ee/legacy/controllers/ee.php(53): EE_Core->generate_page()
#13 [internal function]: EE->index()
#14 ee/ExpressionEngine/Core/Core.php(268): call_user_func_array(Array, Array)
#15 ee/ExpressionEngine/Core/Core.php(124): ExpressionEngine\Core\Core->runController(Array)
#16 ee/ExpressionEngine/Boot/boot.php(184): ExpressionEngine\Core\Core->run(Object(ExpressionEngine\Core\Request))
#17 index.php(164): require_once('...')
#17 index.php(164): require_once('...')

[intoeetive]

@DalizPR thank you for reporting this. The attached PR is providing a fix, you can apply it now, it's a small code change. We'll also include this fix into next patch release ASAP