Persisting TextMorph change the size of the text

I have found this strange bug: when persisting a TextMorph (System set with default font to Accujen 10), when I fetch it back from the DB its font size is Accujen 9 and not 10 anymore

A simple code like that exposes the problem (close the session between the two statements to effectively get the text morph from the database):

(session addBranch: #test with: 'HELLO' asTextMorph ) openInWorld textStyle ==> a TextStyle Accujen10

Then fetching back after a full close of the DB:

(session branch: #test) textStyle ==> a TextStyle Accujen09

Any idea ?

Hilaire