When having this configuration:

<transaction
        transactionMode="TRANSACTIONAL"
        transactionManagerLookupClass="org.infinispan.transaction.lookup.JBossStandaloneJTAManagerLookup"/>
    <locking isolationLevel="REPEATABLE_READ" writeSkewCheck="true" />

When a write skew check is failed, the following exception is propagated to the user code:

org.infinispan.CacheException: Detected write skew - concurrent removal of entry!
at org.infinispan.container.entries.RepeatableReadEntry.performLocalWriteSkewCheck(RepeatableReadEntry.java:75)
at org.infinispan.container.entries.RepeatableReadEntry.copyForUpdate(RepeatableReadEntry.java:52)
at org.infinispan.container.EntryFactoryImpl.wrapEntryForRemove(EntryFactoryImpl.java:133)
at org.infinispan.interceptors.EntryWrappingInterceptor.visitRemoveCommand(EntryWrappingInterceptor.java:158)
at org.infinispan.commands.write.RemoveCommand.acceptVisitor(RemoveCommand.java:72)
at org.infinispan.interceptors.base.CommandInterceptor.invokeNextInterceptor(CommandInterceptor.java:116)
at org.infinispan.interceptors.locking.OptimisticLockingInterceptor.visitRemoveCommand(OptimisticLockingInterceptor.java:173)
at org.infinispan.commands.write.RemoveCommand.acceptVisitor(RemoveCommand.java:72)

The user code is catching the exception, and attempts a rollback. The rollback fails with:

WARN [jta] (main) ARJUNA016045: attempted rollback of < formatId=131077, gtrid_length=29, bqual_length=36, tx_uid=0:ffffac11823e:8e2d:4fc39246:2669f, node_name=1, branch_uid=0:ffffac11823e:8e2d:4fc39246:266a4, subordinatenodename=null, eis_name=0 > (TransactionXaAdapter{localTransaction=LocalXaTransaction{xid=< formatId=131077, gtrid_length=29, bqual_length=36, tx_uid=0:ffffac11823e:8e2d:4fc39246:2669f, node_name=1, branch_uid=0:ffffac11823e:8e2d:4fc39246:266a4, subordinatenodename=null, eis_name=0 >} LocalTransaction{remoteLockedNodes=null, isMarkedForRollback=false, transaction=TransactionImple < ac, BasicAction: 0:ffffac11823e:8e2d:4fc39246:2669f status: ActionStatus.ABORTING >, lockedKeys=null, backupKeyLocks=null, viewId=-1} org.infinispan.transaction.xa.LocalXaTransaction@99a9}) failed with exception code XAException.XAER_NOTA
javax.transaction.xa.XAException
at org.infinispan.transaction.xa.TransactionXaAdapter.getLocalTransactionAndValidateImpl(TransactionXaAdapter.java:245)
at org.infinispan.transaction.xa.TransactionXaAdapter.rollback(TransactionXaAdapter.java:134)
at com.arjuna.ats.internal.jta.resources.arjunacore.XAResourceRecord.topLevelAbort(XAResourceRecord.java:345)
at com.arjuna.ats.arjuna.coordinator.BasicAction.doAbort(BasicAction.java:2876)
at com.arjuna.ats.arjuna.coordinator.BasicAction.doAbort(BasicAction.java:2855)
at com.arjuna.ats.arjuna.coordinator.BasicAction.Abort(BasicAction.java:1618)
at com.arjuna.ats.arjuna.coordinator.TwoPhaseCoordinator.cancel(TwoPhaseCoordinator.java:118)
at com.arjuna.ats.arjuna.AtomicAction.abort(AtomicAction.java:188)
at com.arjuna.ats.internal.jta.transaction.arjunacore.TransactionImple.rollbackAndDisassociate(TransactionImple.java:1247)
at com.arjuna.ats.internal.jta.transaction.arjunacore.BaseTransaction.rollback(BaseTransaction.java:134)

as in org.infinispan.transaction.xa.TransactionXaAdapter.getLocalTransactionAndValidateImpl(Xid, XaTransactionTable) the operation

LocalXaTransaction localTransaction = txTable.getLocalTransaction(xid);

returns null.

This happens as the method org.infinispan.interceptors.TxInterceptor.enlistWriteAndInvokeNext(InvocationContext, WriteCommand) is removing a reference to the local transaction on line 218

I've removed the cleanup line and it fixes my problem: I'm now correctly able to rollback transactions and try again. Still I'm uncomfortable with that change..