Redmine

When copying a a task with Read Only Custom fields to another project the values disapper.
Is this a known issue or am I possible doing something wrong? Could this be a fix for this issue:
#22342

We're using:
Redmine version 3.1.1.stable
Ruby version 1.9.3-p125 (2012-02-16) [i386-mingw32]
Rails version 4.2.4
Environment production
Database adapter Mysql2