My new bookmark is always automatically deleted

I hope, this is the right place to point this out. If not, pleas say me, where the right place would be.

I have a HDD with linux (sda) and I have a HDD with Windows 10 (sdb).

How to reproduce: My win10 HDD is listed below "devices" in thunar.

1. click this HDD
2. type in your root password
3. You are able to browse thorough sdb now. So make a bookmark of "Program Files"
4. The new bookmark is there where it should be
5. Unhook HDD
6. Close thunar. Logg you out. Logg you in.
7. Open thunar. The bookmark is deleted.
8. click on sdb and type in our root password again.
9. You can not find the bookmark. You have to make it new.

My expectation was, that this bookmark will be kept until I will delete it manually. I think, this would be the sense of creating bookmarks.

Thank you for reproducing. Would appreciate some feedback. Thank you.