JEM5-alpha2 : Unknown column 'a.color' in 'field list'

[jobrusche]

Joomla 6.0.3 - PHP 8.4.6

JEM5-alpa1 was installed before but unable to remove with "Manage extensions" (caused by JEM5)
Manually removed JEM5-alpha1 by deleting DB JEM-tables with the help of PHPmyadmin
Also removed all folders/files create by JEM5-alpha1

Now installed JEM5-alpa2, installation finished without problem.
Goto JEM Contol Panel
Click on Venues
Following messages appears in red : Unknown column 'a.color' in 'field list'

An error has occurred.
1054 Unknown column 'l.color' in 'field list'
Call Stack

Function Location

1 () JROOT/libraries/vendor/joomla/database/src/Mysqli/MysqliStatement.php:138
2 mysqli->prepare() JROOT/libraries/vendor/joomla/database/src/Mysqli/MysqliStatement.php:138
3 Joomla\Database\Mysqli\MysqliStatement->__construct() JROOT/libraries/vendor/joomla/database/src/Mysqli/MysqliDriver.php:972
4 Joomla\Database\Mysqli\MysqliDriver->prepareStatement() JROOT/libraries/vendor/joomla/database/src/DatabaseDriver.php:1753
5 Joomla\Database\DatabaseDriver->setQuery() JROOT/libraries/src/MVC/Model/BaseDatabaseModel.php:162
6 Joomla\CMS\MVC\Model\BaseDatabaseModel->_getList() JROOT/administrator/components/com_jem/models/venueelement.php:79
7 JemModelVenueelement->getData() JROOT/libraries/src/MVC/View/AbstractView.php:171
8 Joomla\CMS\MVC\View\AbstractView->get() JROOT/administrator/components/com_jem/views/venueelement/view.html.php:46
9 JemViewVenueelement->display() JROOT/libraries/src/MVC/Controller/BaseController.php:697
10 Joomla\CMS\MVC\Controller\BaseController->display() JROOT/administrator/components/com_jem/controller.php:50
11 JemController->display() JROOT/libraries/src/MVC/Controller/BaseController.php:730
12 Joomla\CMS\MVC\Controller\BaseController->execute() JROOT/administrator/components/com_jem/jem.php:53
13 require_once() JROOT/libraries/src/Dispatcher/LegacyComponentDispatcher.php:71
14 Joomla\CMS\Dispatcher\LegacyComponentDispatcher::{closure:Joomla\CMS\Dispatcher\LegacyComponentDispatcher::dispatch():70}() JROOT/libraries/src/Dispatcher/LegacyComponentDispatcher.php:73
15 Joomla\CMS\Dispatcher\LegacyComponentDispatcher->dispatch() JROOT/libraries/src/Component/ComponentHelper.php:361
16 Joomla\CMS\Component\ComponentHelper::renderComponent() JROOT/libraries/src/Application/AdministratorApplication.php:150
17 Joomla\CMS\Application\AdministratorApplication->dispatch() JROOT/libraries/src/Application/AdministratorApplication.php:206
18 Joomla\CMS\Application\AdministratorApplication->doExecute() JROOT/libraries/src/Application/CMSApplication.php:320
19 Joomla\CMS\Application\CMSApplication->execute() JROOT/administrator/includes/app.php:58
20 require_once() JROOT/administrator/index.php:32

The System Dashboard/Maintenance shows 1 error in the JEM database
Problem
Table '###_jem_venues' has the wrong type or attributes for column 'latitude' with type decimal(10,6). (From file 5.0.0.sql.)
Table '###_jem_venues' has the wrong type or attributes for column 'longitude' with type decimal(10,6). (From file 5.0.0.sql.)
Table '###_jem_categories' does not have index 'idx_parent'. (From file 5.0.0.sql.)
40 database changes were checked.
79 database changes did not alter table structure and were skipped.

"Update structure" cured the database issue, but the "unknown column 'l.color' "remains