Red Alert when IPLing a z/OS 1.9 member in a JES2 MAS

Last Saturday there was a new Red Alert :

“Users may experience data loss from JES2 spool volumes when IPLing a z/OS 1.9 member in a JES2 MAS while any spool volumes are in a draining status (…)JES2 DISASTROUS ERRORS (DISTERRs) such as CBIMPL4 and CBIMPL12 DISTERRs will occur as JES2 processes jobs on the affected volumes; these jobs and their data will be lost”.

For the moment the recommended action is not to perform this action and to install “the ++APAR or the PTF once it becomes available shortly”. So you’ll have to check for updates until it becomes available.
It’s APAR OA23615.