So, as we all remember, you can specify a DCB address for LINK/LOAD, which is an open BPAM DCB pointing at a PDS concatenation from which CSV looks for the requested load module. This makes LINK/LOAD (and CSVDYLPA) flexible and can help with debugging or a quick, temporary override.
Unfortunately, if you specify DCB=(r) and that register does not point to a DCB, you don't get a fancy return code saying the DCB was not a DCB. No, what you will probably get is a strange S0C4-0011 in CSVGETMD in the nucleus.
Moral of the story: if you are cloning code, and you use lots of register operands in your macro invocations, make sure you load all the registers.
Note: CSVDYLPA has additional checks on the DCB parameter and it will give return and reason codes.