BIG-IP : completely delete data-group

F5 BIG-IP 11.4.1 Build 635.0 Hotfix HF2 LTM VE ESXi

via admin browser I perform following steps :

Main > Local Traffic > iRules > Data Group List > select data group > delete "my-data-group"

Main > System > File Management > Data Group File List > select data-group file > delete "my-data-group"

Then ssh to f5-device server and navigate to this dir :

/config/filestore/files_d/Common_d/data_group_d/

I expect to not find any file with name

my-data-group

... but instead I see :

-rw-r--r-- 1 root   apache      62 Sep  8 22:25 :Common:my-data-group_64015_18

For some reason BIG-IP is retaining an underlying data-group file of same name as the external data-group & associated file that I deleted.

1. Why is this ?

2. Can I safely delete this file ?