Partial results prevents client scanner reset on DNRIOEs

I have a following problem after migration from CDH 5.4.5 to CDH 5.5.1.

I have 2 scanners, one for table A, second for table B. Data read by those scanners are joined online to a single consumer. Depending on nature of data, one of the scanner can be idle for variable period of time. When conditions are good, or maybe wrong, server reply with UnknownScannerException, which is, if I understand correctly, signal for ClientScanner to reser connection. And here is where I get NullPointerException.

I believe the problem is, that CDH 5.5.1 incorporated HBASE-13090, which does hard enable partial results capability between hbase client and server. When ClientScanner hits an error, those parial results are not cleaned up. In other words, I can not see in CDH 5.5.1 source code lines 411-413 from
https://git-wip-us.apache.org/repos/asf?p=hbase.git;a=blob;f=hbase-client/src/main/java/org/apache/hadoop/hbase/client/ClientScanner.java;hb=abe3796a9907485c875932caa5f1c82071495c0f