Same for me as well. I can set the defaults to whatever, save the file, then reopen in LO (I am using Impress), and it is back at Liberation Sans 18.
This is a real problem for us, as we use LO and our clients use MS Powerpoint
open pptx in powerpoint, make changes, save as pptx
open saved pptx file in LO Impress, do whatever you want to the defaults, save it as pptx (no changes)
open the pptx saved by LO in step 2 above in Powerpoint
All of the blank cells in all the tables in the pptx file are all changed to Liberation Sans 18
Which trashes the format of all the tables as the rows get bigger
if you open this same file again in LO the tables are all fine, but if you click on a blank cell in a table and look at the character properties, they are all Liberation Sans 18
(somehow LO knows not to change the row size if cell has no text, but I think in powerpoint the font /size is associated with the cell)
Sigh - this will cost me several hundred powerpoint licences
I have downvoted the question for the following reasons:
And actually you used vague wording. It isn't clear if you want to see new or existing documents in other fonts (your "When I create a document the Arial 12 is there for me" might imply that new documents actually have your preferred font set; but then why do you expect existing documents to have font different from what is set in them?) - so your "like a default is supposed to perform" shows misunderstanding what "default" is (it is used when no explicit font is set).
I had the same problem even though I assigned a template. I understand the OP's frustration nothing vague about it. Luckily the answer below fixed it...
Well I 100% agree, even after following recommended steps to stop this fugly font from being used it still appears even in my own spreadsheets.
How do we stop this font from being used as the default in all instances other than those where it has been explicitly set by the person who created the document?????
@User1001: First of all - are you talking about Calc? what has it to do with this "question" tagged "Writer"?
Then - you again do nothing to describe what your problem is (is that a new age fashion?). You could at least suspect that not everyone has the same problem; and thus, at least some information would be useful to others to understand you (as well as OP here): your OS; LO version; a sample document where you see the problem; exactly how it was created; why do you think it should be different; etc. Because it's possibly some configuration problem; or some version bug; or an issue of some file format; or related to specific way of creation; or whatever - but we know nothing.