Error updating NextcloudPi from 20.0.0beta4 to RC2 due to Dashboard

Here are details on the testing of 20.0.0beta4 update process to rc2.
Here is updater.log

Error I received during update process:

Create backup
Could not copy "/data/nextcloud/apps/dashboard/js/" to "/data/nextcloud/data/updater-ochxgtum9iy3/backups/nextcloud-"

Now I’m seeing:

It looks like you are trying to reinstall your Nextcloud. However the file CAN_INSTALL is missing from your config directory. Please create the file CAN_INSTALL in your config folder to continue.

And Nextcloud tries to re-install itself if I manually touch CAN_INSTALL && chmod www-data:www-data CAN_INSTALL from …/config directory.

/var/www/nextcloud/data# ls
Talkbridge	      index.html	  nextcloud.log		updater.log
appdata_ochxgtum9iy3  ncp		  nextcloud.log.1
audit.log	      ncp-update-backups  tmp
files_external	      news		  updater-ochxgtum9iy3