Update in procedure not working

I know this is going to turn out to be pretty simple, but for the life of
me I cannot see the issue.

This is all within a procedure:

I'm chaining out to a file with a key using a Ds named InDs defined as
*INPUT. Works perfectly, get a hit and I have the record.

I copy InDs to a Ds named OutDs defined as an *OUTPUT, I update the OutDs
with a variety of new values that are needed and then execute the
following statement:

Update RdCobex OutDs;

Executes fine, no errors or anything... but the record is never updated.

Here are the DS definitions:

520 D InDs ds LikeRec(rdCobEx:*Input)
521 D OutDs ds LikeRec(RdCobex:*Output)

Here is the file declaration:

512 FDepndCobExuf e k Disk