Steps to reproduce:

• Make a clean ezplatform installation with ezstudio.
• Go to the eZ backend
• Rename the field definition with identifier 'description' to something else. [Admin Panel->Content Types->Content->Landing Page])
• Go back to the Page-Tab and try to add some blocks to a landing_page
• Adding blocks will not work

You will get an JS error in your browser console:

TypeError
columnNumber: 40
fileName: ".../_ezcombo?io-upload-iframe/io-upload-iframe-min.js&queue-promote/queue-promote-min.js&io-queue/io-queue-min.js&/bundles/ezsystemspersonalizedblock/js/plugins/pb-block-serviceplugin.js&/bundles/ezstudioui/js/views/services/plugins/ezs-layoutselectorplugin.js&/bundles/ezstudioui/js/models/ezs-collectionmodel.js&/bundles/ezstudioui/js/helpers/ezs-guid-generator.js&/bundles/ezstudioui/js/models/ezs-pageblockmodel.js&/bundles/ezstudioui/js/lists/ezs-pageblockmodellist.js&/bundles/ezstudioui/js/models/ezs-pagezonemodel.js&/bundles/ezstudioui/js/lists/ezs-pagezonemodellist.js&/bundles/ezstudioui/js/models/ezs-pagemodel.js&/bundles/ezsystemsformbuilder/js/plugins/fb-formblock-serviceplugin.js&/bundles/ezsystemsformbuilder/js/plugins/fb-formblock-restclientplugin.js&/bundles/ezstudioui/js/views/services/ezs-landingpagecreatorservice.js&/tpl/handlebars/locationpreviewview-ez-template.js&/bundles/ezstudioui/js/views/ezs-locationpreviewview.js&/bundles/ezstudioui/js/views/services/plugins/ezs-loadcontentpreviewplugin.js"
lineNumber: 1223
message: "this.get(...).get(...).description is undefined"
stack: "_getViewParameters@.../_ezcombo?io-upload-iframe/io-upload-iframe-min.js&queue-promote/queue-promote-min.js&io-queue/io-queue-min.js&/bundles/ezsystemspersonalizedblock/js/plugins/pb-block-serviceplugin.js&/bundles/ezstudioui/js/views/services/plugins/ezs-layoutselectorplugin.js&/bundles/ezstudioui/js/models/ezs-collectionmodel.js&/bundles/ezstudioui/js/helpers/ezs-guid-generator.js&/bundles/ezstudioui/js/models/ezs-pageblockmodel.js&/bundles/ezstudioui/js/lists/ezs-pageblockmodellist.js&/bundles/ezstudioui/js/models/ezs-pagezonemodel.js&/bundles/ezstudioui/js/lists/ezs-pagezonemodellist.js&/bundles/ezstudioui/js/models/ezs-pagemodel.js&/bundles/ezsystemsformbuilder/js/plugins/fb-formblock-serviceplugin.js&/bundles/ezsystemsformbuilder/js/plugins/fb-formblock-restclientplugin.js&/bundles/ezstudioui/js/views/services/ezs-landingpagecreatorservice.js&/tpl/handlebars/locationpreviewview-ez-template.js&/bundles/ezstudioui/js/views/ezs-locationpreviewview.j…"
_proto_:

Which is actually this line:

vendor/ezsystems/studio-ui-bundle/Resources/public/js/views/services/ezs-landingpagecreatorservice.js Line 167
isDescriptionRequired: this.get('contentType').get('fieldDefinitions').description.isRequired,

Soo when the field type "description" does not exist the function should return at least "false" here.