Created attachment 92148 [details]
short name gets  inside the frame.....the short name outside of the frame would be correct
If your are inserting a new bibliography entry inside a frame the short name is going to be . I found a german forum where this has been reported a long time ago. If you're inserting the same entry outside the frame the entry inside gets updated with correct short name.
Steps to reproduce:
1. Insert an image
2. right click and create a caption (frame gets inserted around the image
3. insert a new bibliography entry behind the caption
short name is going to be 
short name should be the correct number
Operating System: All
Version: 220.127.116.11 release
As far as I correctly understand the online help, I found the following (LibO 18.104.22.168 on Win7) :
- to insert a "new bibliography entry" : Insert/indexes & Tables.../bibliography entry
- the bibliography entry must exist before you can insert its reference ; if it's not yet the case, button "new" to create it ; this is the place were you give it a short name,
- when/if the bibliography entry exists, you see it in the "short name" drop down list, you are able to select it (whichever in bibliography database or in document content), then button "insert" and "close",
- the reference displays as a number or the short name, the choice is made in Insert/indexes & Tables.../indexes & Tables.../"index/table tab"/type bibliography Tab.
From my experiments, all this stuff works well, either in basic text or in frames.
The help is correct.
I tried it again on another computer (Lib 22.214.171.124) and got the same problem.
Insert an image
get the cursor at the end of the caption
insert a bibliography entry (old or new one isn't relevant)
(the short name should be displayed)
activate nummerize entrys (" the reference displays as a number or the short name, the choice is made in Insert/indexes & Tables.../indexes & Tables.../"index/table tab"/type bibliography Tab."
now the entry should be displayed with  (or higher if there has been entrys ealier) but the entr<y gets number 
I also tried entering a secound picture with an another bibliography entry and this entry also gets the numerb 
I fyou want, i can take a few more screenshots or a short video
Created attachment 92279 [details]
OK, I caught it (in the second frame)! So reproduced with LibO 126.96.36.199 on Win7
*** This bug has been marked as a duplicate of bug 46933 ***