Unshare doesn't work, falls back to share

Can anyone test to share a file and unshare again whether unshare is working or not ?

Nextcloud version (eg, 10.0.2):12.0.3
Operating system and version (eg, Ubuntu 16.04): Debian 9
Apache or nginx version (eg, Apache 2.4.25): Nginx 1.10.3
PHP version (eg, 5.6): 7.0.19
Is this the first time you’ve seen this error?:
Yes but happening for all files

Can you reliably replicate it? (If so, please outline steps):
1- upload a file
2- Click Share button
3- Automatically shares without checking “Share Link” checkbox
4- Uncheck “Share Link” checkbox, immediately checkbox ticks again and shares immediately. Cannot remove shared files/folders

The issue you are facing:
Cannot unshare any file or folder

The output of your Nextcloud log in Admin > Logging:

Info admin_audit The file “/DSC_0041.JPG” with ID “4242” has been shared via link with permissions “1” (Share ID: 19) 2017-09-20T20:15:44+0300
Info admin_audit The file “/DSC_0041.JPG” with ID “4242” has been unshared (Share ID: 18) 2017-09-20T20:15:44+0300
Info admin_audit The file “/DSC_0041.JPG” with ID “4242” has been shared via link with permissions “1” (Share ID: 18) 2017-09-20T20:15:40+0300
Info admin_audit Preview accessed: “/DSC_0041.JPG” (width: “473”, height: “267” crop: “”, mode: “cover”) 2017-09-20T20:15:38+0300
Info admin_audit Preview accessed: “/DSC_0041.JPG” (width: “32”, height: “32” crop: “1”, mode: “fill”) 2017-09-20T20:15:35+0300
Info admin_audit File written to: “//DSC_0041.JPG” 2017-09-20T20:15:35+0300
Info admin_audit File created: “//DSC_0041.JPG” 2017-09-20T20:15:35+0300

The output of your config.php file in /path/to/nextcloud (make sure you remove any identifiable information!):

<?php $CONFIG = array ( 'instanceid' => 'removed', 'passwordsalt' => 'removed', 'secret' => 'removed', 'trusted_domains' => array ( 0 => 'example.com', ), 'datadirectory' => '/media/cloud', 'overwrite.cli.url' => 'https://example.com', 'dbtype' => 'mysql', 'version' => '12.0.3.3', 'dbname' => 'nextcloud', 'dbhost' => 'localhost', 'dbport' => '', 'dbtableprefix' => 'oc_', 'mysql.utf8mb4' => true, 'dbuser' => 'nextcloud', 'dbpassword' => '****', 'loglevel' => 1, 'logtimezone' => 'Europe/Berlin', 'logfile' => '/var/log/nextcloud.log', 'log_rotate_size' => 104857600, 'cron_log' => false, 'installed' => true, 'filesystem_check_changes' => 1, 'quota_include_external_storage' => false, 'knowledgebaseenabled' => false, 'memcache.local' => '\\OC\\Memcache\\APCu', 'filelocking.enabled' => 'true', 'memcache.locking' => '\\OC\\Memcache\\Redis', 'redis' => array ( 'host' => '/var/run/redis/redis.sock', 'port' => 0, 'timeout' => 0.0, ), 'maintenance' => false, 'theme' => '', 'enable_previews' => true, 'mail_from_address' => 'postmaster', 'mail_smtpmode' => 'php', 'mail_smtpauthtype' => 'LOGIN', 'mail_domain' => 'example.com', 'updater.secret' => 'SomeSecretChars', ); The output of your Apache/nginx/system log in `/var/log/____`: {"reqId":"UixjgbIw6Ku3ALOctCou","level":1,"time":"2017-09-20T19:08:23+02:00","remoteAddr":"192.168.1.5","user":"mucahid","app":"admin_audit","method":"DELETE","url":"\/ocs\/v2.php\/apps\/files_sharing\/api\/v1\/shares\/14?format=json","message":"The file \"\/bbm_end_call.wav\" with ID \"824\" has been unshared (Share ID: 14)","userAgent":"Mozilla\/5.0 (X11; Linux x86_64) AppleWebKit\/537.36 (KHTML, like Gecko) Ubuntu Chromium\/60.0.3112.113 Chrome\/60.0.3112.113 Safari\/537.36","version":"12.0.3.3"} {"reqId":"00cdgpV4r73Ho8wOg0vP","level":1,"time":"2017-09-20T19:08:23+02:00","remoteAddr":"192.168.1.5","user":"mucahid","app":"admin_audit","method":"POST","url":"\/ocs\/v2.php\/apps\/files_sharing\/api\/v1\/shares?format=json","message":"The file \"\/bbm_end_call.wav\" with ID \"824\" has been shared via link with permissions \"1\" (Share ID: 15)","userAgent":"Mozilla\/5.0 (X11; Linux x86_64) AppleWebKit\/537.36 (KHTML, like Gecko) Ubuntu Chromium\/60.0.3112.113 Chrome\/60.0.3112.113 Safari\/537.36","version":"12.0.3.3"} --- Remember, this information may be requested if it isn't supplied; for fastest response please provide as much as you can :heart: Feel free to use a pastebin service, otherwise log files can be indented with 4 spaces on each line to present them in a friendlier way on the forum.

Did some more troubleshooting and realized this is happening only with Chromium browser, both firefox and android client looking good.
Anyone using Ubuntu w/ Chromium would be great if can test this issue.
Thanks

I have the same issue with Chrome 61.0.3163.100 on mac.
When you unlink, tends to succeed, but after 1 sec, the link option automatically activates.
No problem on Safari

Same with chrome 62

Must be a bug. Created https://github.com/nextcloud/server/issues/6990