My questions are:
1) if this only occurs at time change and hasn't recurred - why really spend the effort researching the problem? Just go on, and try to avoid running the job(s) during the next time change.
2) if really necessary to reproduce, is there a test LPAR that you can simulate the time change to recreate the problem? Make sure that you use run-time options TERMTHDACT(UAIMM) and TRAP(ON,NOSPIE). From the description is Quick Reference, the return code 15 means that the save area blocks were no longer intact - perhaps content supervision has a problem with time changes (don't know for sure, it has been a long time since I messed around with the mainframe, even longer with OS control blocks!). But bottom line, it seems to me to be hard to blame on IDMS, seems more like an OS and/or LE issue to me.
Dan Miley