Thank you for your reply.
Good to know that enabling compatibility mode before or after loading the load doesn't have any effect.
I didn't drop/recreate all the SP and views but I can tell you I recreated a similar view and it causes the same issue.
I had a look at your link yes. I have run 'dbcc upgrade_object' several times already, on the view and the procedures calling the view, and it won't solve anything.
I've seen a similar post about the problem I have when executing the code itself of the view in a "normal" adhoc query (errors saying the tables are not found) : SAP Sybase Forums - ASE - Backup and Recovery - PRoblem after restore - Object does not exist.
Could it be the same problem for me?
Although I've tried splitting the SQL query and executing the parts individually and it works without any trouble. Problem is when the 2 parts of the view are put together. It may be something that was possible with ASE 12.5.4 but not with 15.7 and that compatiblity mode doesn't solve. My view consists of an union a two selects where both have left joins, case when then else, not in and a final group by (adding an order by doesn't help, as I tried).
PS : I don't have access to the production server where the dump is actually from (but I could if it is really necessary)