Error 1054 on DROP INDEX for tables having virtual column and view referencing it

SQL State  : 42S22

Error Code : 1054

Message    : (conn=63) Unknown column '`omega_label`.`du`.`sessionId`' in 'GENERATED ALWAYS'

Statement  : DROP INDEX uttUser ON dialog_utterances

CREATE TABLE IF NOT EXISTS `dialog_utterances` (

   `id` bigint(20) NOT NULL AUTO_INCREMENT,

   `sessionId` char(40) NOT NULL,

   `messageNo` smallint NOT NULL,

   `conversationUUID` varchar(50) AS (CONCAT(sessionId, '#', messageNo)) VIRTUAL,

   `uttUser` varchar(300) DEFAULT NULL,

   PRIMARY KEY (`id`),

   KEY (uttUser(191)),

   UNIQUE KEY (`sessionId`, `messageNo`)

) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE utf8mb4_general_ci;

CREATE TABLE IF NOT EXISTS `dialog_tags` (

     `tagId` bigint(20) NOT NULL,

     `dialogId` bigint(20) NOT NULL,

     PRIMARY KEY (`tagId`, `dialogId`),

     FOREIGN KEY fk_dialog_tags__dialog_utterances (dialogId) references `dialog_utterances` (id) ON DELETE CASCADE ON UPDATE NO ACTION

) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE utf8mb4_general_ci;

CREATE TABLE IF NOT EXISTS `tags` (

  `id` bigint(20) NOT NULL AUTO_INCREMENT,

  `tag` varchar(191) NOT NULL,

  PRIMARY KEY (`id`),

  UNIQUE KEY (`tag`)

) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE utf8mb4_general_ci AUTO_INCREMENT=100;

CREATE OR REPLACE VIEW `dialog_tags_view` AS

select dt.*, du.uttUser, t.tag

from dialog_tags dt

     join dialog_utterances du

          on dt.dialogId = du.id

     join tags t

          on dt.tagId = t.id;

DROP INDEX uttUser ON dialog_utterances;