The bug might be in NCluster jdbc driver

com.asterdata.ncluster.util.NClusterException: Bad value for type BigDecimal : NaN
    at com.asterdata.ncluster.jdbc2.AbstractJdbc2ResultSet.toBigDecimal(AbstractJdbc2ResultSet.java:2740)
    at com.asterdata.ncluster.jdbc2.AbstractJdbc2ResultSet.getBigDecimal(AbstractJdbc2ResultSet.java:2161)
    at com.asterdata.ncluster.jdbc2.AbstractJdbc2ResultSet.internalGetObject(AbstractJdbc2ResultSet.java:130)
    at com.asterdata.ncluster.jdbc3.AbstractJdbc3ResultSet.internalGetObject(AbstractJdbc3ResultSet.java:38)
    at com.asterdata.ncluster.jdbc2.AbstractJdbc2ResultSet.getObject(AbstractJdbc2ResultSet.java:2465)
    at com.aquafold.aquacore.scripts.engine.AFScriptContext.createQueryResultSet(AFScriptContext.java:3131)
    at com.aquafold.aquacore.scripts.engine.AFScriptContext.executeScriptStatements(AFScriptContext.java:2103)
    at com.aquafold.datastudio.queryanalyzer.QueryThread.run(QueryThread.java:416)

the block symbol is \uFFFD, "replacement character"

Fixed the case where Nan value is rendered with \uFFFD.

However, I don't think the table data editor handles NaN values correctly.  Try editing a row which cotnains NaN, or enter a "NaN string into a cell.