A search of solved cases @ sybase.com shows a half dozen CRs that *might* apply in your case ... hard to tell without knowing RS version as well as details about the PDB.
I'd suggest opening a tech support case to see if a) one of those half dozen CRs apply or 2) if you're hit a new problem.
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Otherwise you could try to get the DIST up again via ...
1 - Issue the 'resume distributor/skip transaction' command to see if this will flush the problematic transaction from the queue
or
2 - If you know/understand how to zap transactions you could certainly try 'cleaning up' the DIST queue. [NOTE: I don't recommend you do this unless you really, Really, REALLY understand what you're doing otherwise you could (further) corrupt the queue.]
Keep in mind that implementing either of these options could leave your PDB and RDB out of sync. In a worse case scenario a discarded DDL command (eg, 'create table mytable') could cause follow-on replicated DML commands (eg, 'insert mytable') to fail, ymmv.